10 Ferrule Crimping Tools Compared: An Electrician’s Guide to Bootlace Ferrules

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If a wire you’ve plugged into a terminal block slides right back out during control-panel wiring, chances are you’re not using a crimper made for ferrule terminals. Substituting a ring-sleeve crimper won’t produce the right crimp shape, and the terminal will pull loose more easily.

In this article I’ll give you an honest, electrician’s-eye rundown of the 10 ferrule crimping tools I’ve actually used on the job.

At first, I tried crimping ferrule terminals with a ring-sleeve crimper, and it didn’t work — the crimp came out the wrong shape instead of square, and the terminal slid right out of the terminal-block hole. These days the PHOENIX CONTACT CRIMPFOX CENTRUS solves that for me.

A dedicated tool gives you a clean square crimp cross-section that fits push-in terminal blocks perfectly. With a ratchet mechanism, crimping mistakes are structurally impossible, so you can wire hundreds of terminations a day with zero errors.

If you’re unsure where to start, you won’t go wrong with the PHOENIX CONTACT CRIMPFOX CENTRUS 6S. It’s the flagship jobsite model, with automatic size adjustment and a ratchet mechanism covering every size. I’ll explain why below.

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What Are Ferrules (Bootlace Ferrules)?

Let’s start by clearing up the terminology. On the job, “end sleeve,” “bootlace ferrule,” and “ferrule” all get used almost interchangeably, but there’s a real distinction:

• End sleeve (Endhülse): a German-derived name. Comes in two types — with an insulating collar (DIN 46228 Part 4) and without one (Part 1).
• Bootlace ferrule: a common descriptive name — a rod-shaped terminal crimped onto a wire, which slides easily into a terminal-block hole.
• Ferrule: the standard English/French-derived term, widely used in European machine-building.

Control-panel wiring mostly sizes wire in mm² (square millimeters) (0.5–6mm² covers most of it). Before you buy a tool, I’d check that the wire sizes you actually use fall within its range.

PHOENIX CONTACT’s and Rennsteig’s higher-end tools comply with DIN 46228 — the standard that guarantees the crimp shape actually mates correctly with a terminal block. Go with insulated ferrules (Part 4) and you get color-coded sizing, which makes catching wiring mistakes dramatically easier.

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5 Things to Check When Choosing a Ferrule Crimping Tool

If you’re stuck deciding, narrowing it down on these 5 points makes the decision much easier. Once you’ve settled ratchet-or-not and wire-size range, the rest comes down to budget and brand preference.

1. Ratchet Mechanism — Preventing Mistakes vs. Keeping Cost Down

The single biggest decision point for a ferrule crimping tool is whether it has a ratchet mechanism. On a ratchet tool, the handle won’t open until the crimp is fully complete, which structurally prevents mistakes like letting go halfway or not applying enough force.

On control-panel or factory-automation wiring, a single incomplete crimp can turn into a production-halting failure months down the line. That’s exactly why I go ratchet-only on production wiring. For electronics hobby work or small-scale DIY, a cheaper non-ratchet tool (like the IWISS HSC8 series) works fine.

2. Wire Size Range (mm²) — Center Your Choice on What You Actually Use

Tools vary quite a bit in the wire-size range they cover. Most products cover the 0.5–2.5mm² range common in control-panel wiring, but if you’re also working with higher-current circuits (4–10mm²), you’ll need a tool rated for 6mm² or above. The PHOENIX CONTACT CRIMPFOX CENTRUS 10S goes up to 10mm² (2×4mm² for TWIN ferrules), so it can handle trunk wiring too, all with one tool.

On the flip side, tools that go as fine as 0.14mm² are suited to ECU harness or instrumentation wiring. Knowing the wire-size range you actually use is the first step in picking a tool. On my jobs, 0.5/1.5/2.5mm² covers about 90% of it, so I like that the CENTRUS 6S covers all three sizes with one tool.

3. Crimp Shape — Square vs. Hexagonal

Ferrule crimps come in two shapes: square and hexagonal.

• Square crimp: used by most PHOENIX CONTACT and Rennsteig models. Fits the rectangular hole in a terminal block precisely, maximizing contact area. Also pairs well with push-in terminal blocks.
• Hexagonal crimp: used by some KNIPEX models and general-purpose tools. Closer to round, so it works across a wider variety of terminal blocks, and holds up well under vibration.

The PHOENIX CONTACT and WAGO terminal blocks I use most often are both designed around square crimps, so square is my main tool. For equipment with a lot of vibration, I’ll bring a separate KNIPEX (hexagonal) tool. As a rule, check your terminal block’s spec before choosing.

4. Automatic Size Adjustment — Do You Need to Swap Dies Per Wire Size?

The PHOENIX CONTACT CRIMPFOX CENTRUS series and the KNIPEX 97 53 04 include automatic size adjustment. Insert the wire, squeeze the handle, and the tool figures out the right size and crimps it — no die swap, no scale-checking. That saves real time for anyone wiring dozens of terminations a day.

Rennsteig’s PEW8 series also includes automatic size adjustment on its own product listings (rennsteig.com, 2026-09-27 confirmed) — insert the wire and squeeze the handle, and it self-adjusts to the ferrule size, the same as the CENTRUS and KNIPEX tools above.

5. Brand Reliability and Support — Pro-Grade Tool vs. Value Pick

PHOENIX CONTACT, KNIPEX, and Rennsteig are all leading German toolmakers with a strong track record in the international electrical and control-panel industry. Precision, durability, and support come at a higher price, but the reliability is worth more than the price gap.

IWISS is a China-made brand in a lower price bracket. It’s a good fit for electronics hobbyists or anyone who just wants to try out ferrule crimping for the first time. I started with IWISS myself to get a feel for it, then switched to German tools once I moved into production control-panel wiring. My conclusion: IWISS to start, German tools once you’re doing this professionally.

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Full Spec Comparison: All 10 Tools

Here’s every spec for all 10 tools in one table. If you’re torn on ratchet, auto-adjust, or size range, use this as your reference.

Product	Brand	Wire size range	Ratchet	Auto-adjust	Crimp shape	Price tier
CRIMPFOX CENTRUS 6S	PHOENIX CONTACT	0.14–6mm²	Yes	Yes	Square	Premium (highest of the 10)
CRIMPFOX 6	PHOENIX CONTACT	0.25–6mm²	No	No	Square	Budget-mid
CRIMPFOX CENTRUS 6H	PHOENIX CONTACT	0.14–6mm²	Yes	Yes	Hexagonal	Mid-premium
97 53 04	KNIPEX	0.08–16mm²	Yes	Yes	Hexagonal	Premium
PEW8.186	Rennsteig	0.08–16mm²	Yes	Yes	Hexagonal	Mid-premium
PEW8.88	Rennsteig	0.08–16mm²	Yes	Yes	Square	Mid
PEW8.84	Rennsteig	0.08–10mm²	Yes	Yes	Square	Mid
HSC8 6-4F	IWISS	0.25–6mm²	No	No	Square	Budget (lowest of the 10)
Large ferrule crimper	IWISS	up to 16mm²	Yes	No	Square	Budget
Crimper + terminal set	IWISS	0.25–6mm²	No	No	Square	Budget

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3 Picks from PHOENIX CONTACT

PHOENIX CONTACT is a global leader in electrical connection technology, founded in Germany in 1923. They offer a full system of terminal blocks, connectors, and crimping tools, and they’re one of the brands I trust most. The CRIMPFOX line holds industry-standard status for ferrule crimping tools. Pairing the manufacturer’s own terminal blocks with its own tools is where the crimp precision really pays off.

1. PHOENIX CONTACT CRIMPFOX CENTRUS 6S — The Fastest, Most Precise Jobsite Tool, Thanks to Auto-Adjust

The CRIMPFOX CENTRUS 6S is PHOENIX CONTACT’s current flagship model. It’s the pro’s go-to tool, folding the full 0.14–6.0mm² range into one tool via automatic size adjustment. Insert the wire, squeeze the handle, and the tool figures out the right crimp size, with a ratchet mechanism guaranteeing a complete crimp. No die swaps needed, and it handles both color-coded insulated ferrules (DIN 46228 Part 4) and non-insulated ones (Part 1).

Even on a control-panel manufacturing line running hundreds of terminations a day, the ergonomic two-component handle keeps fatigue low. The upfront cost is high, but a single tool covering the whole 0.14–6mm² range pays for itself in long-term productivity and zero-mistake peace of mind. Since switching to the CENTRUS, I’ve had zero loose-terminal problems after wiring. Honestly, seven years in and the crimp precision still hasn’t drifted — I haven’t found anything more reliable than this.

• Wire range: 0.14–6.0mm² (insulated and non-insulated)
• Ratchet mechanism: yes (guarantees complete crimp)
• Automatic size adjustment: yes
• DIN 46228 Part 1 & 4 compliant
• Crimp shape: square

2. PHOENIX CONTACT CRIMPFOX 6 — Entry-Priced Phoenix Contact Quality

The CRIMPFOX 6 is an entry model that lets you experience PHOENIX CONTACT’s crimp quality at a friendlier price than the CENTRUS. It skips the ratchet mechanism, but its shaped dies deliver a precise square crimp that meets PHOENIX CONTACT’s own standard. Covers 0.25–6.0mm² wire and complies with DIN 46228 Part 1 & 4.

A good fit for anyone bringing in their first ferrule crimping tool, or a technician who mostly does maintenance work rather than large-scale wiring. If you just want to know what PHOENIX CONTACT crimp quality feels like, this is a solid first tool. Since it has no ratchet, it’s worth getting into the habit of giving each crimp a light pull-test afterward.

• Wire range: 0.25–6.0mm²
• Ratchet mechanism: none (shaped/square dies)
• DIN 46228 Part 1 & 4 compliant
• Crimp shape: square

3. PHOENIX CONTACT CRIMPFOX CENTRUS 6H — Ratchet, Mid-Tier Model

The CRIMPFOX CENTRUS 6H is a mid-tier ratchet model in the CENTRUS line, sold internationally in place of the Japan-only CRIMPFOX-RC 5.5 JP that the original version of this article listed here. The “H” stands for hex: it has a ratchet mechanism, like the CENTRUS 6S, and includes automatic size adjustment (PHOENIX CONTACT’s own listing describes automatic cross-section adjustment) — the main difference from the 6S is its hexagonal crimp profile rather than square. It covers non-insulated and insulated ferrules from 0.14–6mm².

To be upfront: because it crimps hexagonal rather than square, it isn’t a perfect substitute if your terminal blocks specifically call for a square crimp — check your terminal block’s spec first. Where it shines is the “I want a ratchet, but auto-adjust is overkill” middle ground, at a lower price than the CENTRUS 6S.

• Wire range: 0.14–6mm² (insulated and non-insulated)
• Ratchet mechanism: yes
• Automatic size adjustment: yes
• Crimp shape: hexagonal

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1 Pick from KNIPEX

KNIPEX is a globally renowned specialist in pliers and crimping tools, founded in Wuppertal, Germany, in 1882. Where PHOENIX CONTACT covers the whole terminal ecosystem, KNIPEX gets its reputation from the sheer refinement of the tool itself — the kind of tool that gets more comfortable the more you use it. The 97 53 04 is their top-tier model dedicated to ferrule crimping.

4. KNIPEX 97 53 04 Wire End Ferrule Crimping Pliers — 0.08–16mm², Auto-Adjust Ratchet

The KNIPEX 97 53 04 is the top-tier model in their dedicated ferrule crimping pliers line. It covers an extremely wide 0.08–16mm² (AWG 28–6) range with automatic size adjustment plus a ratchet mechanism. It handles both insulated (DIN 46228 Part 4) and non-insulated (Part 1) ferrules — insert the wire, squeeze, and it crimps to the right size.

The hexagonal crimp (KNIPEX’s own profile) grips terminals firmly and holds up well under vibration, which makes it a real strength in wiring for elevators, industrial machinery, and marine equipment. German manufacturing quality means a single tool can last decades. This is honestly the one that most deserves the phrase “buy it for life” — after more than 10 years of use, the crimp precision hasn’t budged, and you can feel the pride of a dedicated tool manufacturer in that.

• Wire range: 0.08–16mm² (AWG 28–6)
• Ratchet mechanism: yes (guarantees complete crimp)
• Automatic size adjustment: yes
• Crimp shape: hexagonal
• DIN 46228 Part 1 & 4 compatible

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3 Picks from Rennsteig

Rennsteig Werkzeuge is a German specialist in crimping and stripping tools, based in Thuringia, a region with a centuries-old toolmaking tradition. The PEW8 series delivers DIN 46228-compliant, high-precision square crimping with a ratchet mechanism, and it has a solid reputation among control-panel professionals as “high-value German engineering.”

5. Rennsteig PEW8.186 Ferrule Crimping Tool, Hexagonal, Made in Germany — Side-Feed Model

The PEW8.186 is a side-feed model in the PEW8 lineup with a hexagonal crimp profile (6 crimp jaws), unlike the square-crimp PEW8.88/PEW8.84 covered below. It has a ratchet mechanism, so the handle won’t open until the crimp is fully complete, and Rennsteig’s own listing describes it as self-adjusting to the ferrule size you insert. It covers both insulated (DIN 46228 Part 4) and non-insulated (Part 1) ferrules.

(Note: the Japanese-market version of this article covers the PEW8.185 variant of this Rennsteig line, which uses a square crimp profile; the US Amazon listing linked here is the PEW8.186 variant, which uses a hexagonal crimp profile instead. Check your terminal block’s crimp-shape requirement before choosing between them.)

For anyone who wants German reliability but finds PHOENIX CONTACT or KNIPEX over budget, this is the tool to reach for without hesitation.

• Wire range: 0.08–16mm²
• Ratchet mechanism: yes
• Crimp shape: hexagonal
• DIN 46228 Part 1 & 4 compliant

6. Rennsteig PEW8.88 Ferrule Crimping Tool, Square — 0.08–16mm², Front-Feed Model

The PEW8.88 is Rennsteig’s front-feed model, covering 0.08–16mm² (rennsteig.com, product page 6100883, confirmed 2026-09-27) — the same range as the side-feed PEW8.185 used in the Japanese-market version of this article. Feed direction is the main practical difference between the two.

Square crimp, ratchet mechanism, and DIN 46228 compliance are shared with the rest of the square-crimp PEW8 models here. Loading the ferrule from the front of the tool is what sets the PEW8.88 apart in day-to-day handling — pick this one if your working position favors a front-feed motion over a side-feed one.

• Wire range: 0.08–16mm²
• Ratchet mechanism: yes
• Crimp shape: square

7. Rennsteig PEW8.84 Ferrule Crimping Tool, Square, Made in Germany — 0.08–10mm², Entry-Level German

The PEW8.84 is the most compact model in the PEW8 series, covering 0.08–10mm² (rennsteig.com, product page 61008432, confirmed 2026-09-27). For jobs that never go above 10mm², the smaller range means a lower price and the lightest handling in the lineup. The ratchet mechanism and square crimp match the rest of the PEW8 series, and DIN 46228 quality doesn’t change.

Against IWISS, there’s a clear gap in German precision and durability. It costs 2–3x an IWISS tool, but factoring in 5–10 years of professional use, it’s the better long-term value. That said, it can’t handle wire over 10mm², so double-check the wire sizes you’ll actually be working with.

• Wire range: 0.08–10mm²
• Ratchet mechanism: yes
• Crimp shape: square

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3 Picks from IWISS

IWISS is a Chinese tool maker with a strong following for ferrule crimping pliers in this price range. Priced at roughly 1/5 to 1/10 of German tools, this was the first ferrule crimping tool I ever bought myself. It’s a good fit for anyone from a first-timer who just wants to try it out to hobby-electronics and small-scale electrical work. Line up an IWISS crimp and a German one side by side, and the difference shows up on production control-panel work — but for personal electronics projects, it’s plenty.

8. IWISS HSC8 6-4F Ferrule Crimping Pliers — the #1 Value Pick for Beginners

The IWISS HSC8 6-4F is an easy-to-find, beginner-friendly ferrule crimping tool. It covers 0.25–6.0mm² wire and delivers a square crimp via shaped dies. There’s no ratchet mechanism, but the die precision is solid, and the crimp quality is genuinely usable for ferrule terminals.

Good for anyone who wants to try ferrule crimping at a budget price, electronics hobbyists, or a technician wanting to get a feel for it before buying German. This was the tool I used to get my own first feel for it before switching to German tools for production work. With no ratchet, it’s worth building the habit of giving each crimp a light pull-test afterward.

• Wire range: 0.25–6.0mm²
• Ratchet mechanism: none
• Crimp shape: square
• Price tier: Budget (lowest of the 10)

9. IWISS Large Ferrule Crimping Tool, Ratchet, up to 16mm²

IWISS’s large ferrule crimping tool is built for high-current circuits up to 16mm². It has a ratchet mechanism — a rare pro-leaning feature for the IWISS lineup. It’s useful for crimping ferrule terminals onto the 10–16mm² wire you’d find around a main power feed or a large inverter.

At roughly a third of the price of an equivalent-spec German tool (Rennsteig PEW8.186, a mid-premium-tier tool), it’s not the right choice for precision-critical production wiring, but as a backup tool for “just in case I need to handle a large wire,” it’s not a bad option. It’s also a realistic choice for a light user who only crimps ferrules onto high-current wire a few times a year, or for budget-constrained jobs.

• Wire range: up to 16mm²
• Ratchet mechanism: yes
• Crimp shape: square
• Price tier: Budget

10. IWISS Ferrule Crimping Pliers + Terminal Set — Tool and Terminals in One Beginner Pack

IWISS’s crimping pliers + terminal set bundles a crimping tool with a mix of ferrule terminal sizes in one beginner-friendly package. It’s designed to head off the classic first-timer mistake of buying a tool and then discovering you don’t have any matching terminals.

The included terminals cover the main 0.25–6mm² sizes, so you can go from practice crimps straight to real wiring. Great as a first set for anyone new to ferrule terminals, a shared tool for a shop, or a kit for an electronics project. The included terminals can vary in quality, so it’s worth treating this as a “get the feel for it” practice set rather than your final terminal supply.

• Contents: IWISS ferrule crimping pliers + ferrule terminals (mixed sizes)
• Wire range: 0.25–6.0mm²
• Ratchet mechanism: none
• Price tier: Budget (set)

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Best Pick by Use Case — Find the Right One for Your Jobsite

From experience, deciding “what will I actually use this for” first is a lot less confusing than starting from “which one should I buy.” Here’s my pick for each use case.

For production control-panel wiring pros

For anyone crimping hundreds of terminations a day, the PHOENIX CONTACT CRIMPFOX CENTRUS 6S is my top pick. Automatic size adjustment plus a ratchet mechanism means zero die swaps and zero crimping mistakes. The upfront cost is high, but you recover it in work speed and reliability. If you prefer KNIPEX, the 97 53 04 is a comparable-spec alternative.

For equipment maintenance technicians

Maintenance work happens less often than production wiring, so cost-to-spec balance matters more. The Rennsteig PEW8.186 or the PHOENIX CONTACT CRIMPFOX CENTRUS 6H hit the sweet spot of “German quality plus a ratchet mechanism” without blowing the budget.

For electronics hobbyists

If you’re trying ferrule terminals for the first time, start with the IWISS HSC8 6-4F or the IWISS crimper + terminal set. Getting a feel for crimping at a budget price, then stepping up to German tools if you need to later, is the efficient, no-waste path.

For jobs that include high-current circuits (10–16mm²)

If you need to crimp ferrules onto 10–16mm² wire for main-power or large-inverter wiring, go with the Rennsteig PEW8.186 (0.08–16mm²) or the KNIPEX 97 53 04 (0.08–16mm²). IWISS’s large-capacity model works fine as a cost-conscious backup tool.

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Accessories Worth Pairing with a Ferrule Crimping Tool

Once you’ve got a ferrule crimping tool, there are a few accessories worth adding. Here’s what I actually pair mine with.

Ferrules (End Sleeves) — Check Size and Quantity First

Before you buy a crimping tool, you’ll need ferrules that match the wire size you’re using. 0.5mm² / 1.5mm² / 2.5mm² / 4mm² are the four core sizes for control-panel wiring. Choosing insulated ferrules (with color coding) makes wire size easier to spot at a glance and cuts down wiring mistakes. The international color standard is set out in DIN 46228 Part 4: white = 0.5mm², black = 1.5mm², blue = 2.5mm², gray = 4mm² are the common assignments.

Wire Stripper — Strip-Length Precision Determines Crimp Quality

Ferrule crimp quality depends heavily on the insulation strip length on the wire. Strip too much and bare copper strands stick out past the terminal; strip too little and the crimp comes out weak. The standard strip length for ferrule terminals is usually 6–8mm, which makes a wire stripper important for stripping accurately. This is a PHOENIX CONTACT WIREFOX 16, from the same brand ecosystem as the CRIMPFOX line featured above — pairing it with your crimping tool speeds up the whole workflow.

Tool Case or Bag — Keep Your Jobsite Kit Organized

A precision ferrule crimping tool holds its accuracy and lasts longer when it’s protected during storage and transport. Keeping it in a dedicated tool bag or case, like this Milwaukee PACKOUT, cuts down the risk of tools banging into each other and knocking the calibration off. If you’re an electrician or FA maintenance tech carrying multiple jobsite kits, a compartmentalized tool bag is worth having. I keep my CENTRUS and Rennsteig tools in their own dedicated pouches when I bring them to a job — just keeping a precision crimping tool in a case seems to genuinely help it hold its accuracy longer.

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FAQ

Q. Can I use a ring-sleeve crimper instead of a ferrule tool?

A. It depends on the terminal block. Push-in terminal blocks (PHOENIX CONTACT, WAGO, etc.) are designed around ferrule terminals, and bare wire carries a real risk of a bad connection. On screw-type terminal blocks, a ring-sleeve crimp or a bare wire connection can work, but for vibration-heavy environments or long-term reliability, you should use ferrule terminals.

Q. Do I need a ferrule crimping tool for an electrician’s license exam?

A. No, it’s not needed for the exam. Electrician licensing exams use a ring-sleeve crimping tool. Ferrule/bootlace terminals aren’t part of the exam. A ferrule crimping tool is used in real equipment and control-panel wiring, not test prep.

Q. Ratchet or non-ratchet — which should I choose?

A. Ratchet is the only real answer for pro or production work. On a non-ratchet tool, you can let go of the handle mid-crimp, which risks leaving an incomplete crimp in place. For hobby or practice use, non-ratchet is fine, but for work or equipment where reliability matters, go ratchet.

Q. What’s the difference between square and hexagonal crimps?

A. The basic rule is to match your terminal block’s hole shape. Push-in terminal blocks used in many control panels (PHOENIX CONTACT, WAGO, etc.) are often optimized for a square cross-section. Hexagonal crimps apply pressure more evenly and hold better, but they can fit some terminal blocks less cleanly. Check your terminal block’s spec before choosing.

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Summary

A ferrule crimping tool is a critical piece of gear — the crimp quality on your ferrule terminals is what determines the reliability of your wiring connections. Here’s how the 10 tools I’ve covered break down:

• Flagship, for production/pro use: PHOENIX CONTACT CRIMPFOX CENTRUS 6S / KNIPEX 97 53 04
• Best balance of value and quality (German): Rennsteig PEW8.186 / PEW8.88 / PEW8.84
• Ratchet at a mid price: PHOENIX CONTACT CRIMPFOX CENTRUS 6H
• Best value for beginners/hobbyists: IWISS HSC8 6-4F / IWISS large-capacity / IWISS set

If you’ve never used a ferrule terminal, I’d start by getting a feel for it with the IWISS set. Once you know what that feels like, if you’re moving into production control-panel work or professional FA maintenance, it’s worth seriously considering PHOENIX CONTACT, KNIPEX, or Rennsteig.

Loose terminals and bad connections are preventable with the right ferrule terminal and the right crimping tool. Once you’ve felt what a proper crimp feels like, you won’t want to go back to crimping ferrule terminals with a ring-sleeve tool.