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STM Spark Plug Gapper Tool

STM Tuned Inc.


Vehicle Fitment:
For 12mm or 14mm spark plug threads
See fitments below

The STM Spark Plug Gapping Tool allows for easy handling of your spark plug and gauge for for a smooth, controlled and precise gap. So you can stop banging your plugs on random hard surfaces!

Available for both 12mm or 14mm spark plug threads. Purchase them individually, or buy the set of 2!

Please confirm the thread size for your plugs before purchase.

• USA-made
• Billet aluminum
• Super easy to use tool

12mm Gapper Tool for:
Mitsubishi Lancer Evolution X
Nissan R35 GT-R
Nissan 350Z 2007 - 2009
Nissan 370Z 2009 - 2016
Infinity G35 11/2006 - 2008
Infinity G37 2008 - 2013
Subaru BRZ
Scion FR-S
Subaru 2015+ FA20 WRX

14mm Gapper Tool for:
Mitsubishi Lancer Evolution 1/2/3/4/5/6/7/8/9
Mitsubishi 1G/2G DSM (Eclipse/Talon/Laser)
Mitsubishi 3000GT
Dodge Stealth
Subaru STi 2004-2018
Subaru WRX 2002 - 2014
Nissan 350Z 2003 - 2006
Infinity G35 2003 - 10/2006
Ford Focus ST 2013 - 2017
Ford Focus RS 2016 - 2017
Lamborghini Huracán
Lamborghini Gallardo
Audi R8 V8/V10

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Customer Reviews

Based on 6 reviews
Nice tool

It's a shame no one sells something like this here in Russia. Only those coin type ones, which are pretty much useless for a laser iridium spark plugs.
No more C-clamp as a gap tool:)
BTW, it would be nice if thread size was embossed somewhere on the tool to identify the thread on first sight, instead of checking every time manually (since there are more than one option available).

Great tool

So simple but so needed to safely and easily regap your spark plugs everyone needs this tool!! If you work on your own car that is.

Thanks, Matthew! We definitely agree that this tool is one of those 'must-haves'
Great tool!

A must have! It definitely makes gapping plugs much easier!

Agreed! It's definitely one of our 'must-have' tools : )
Good product, good service

Really convenient little tool for gapping spark plugs. Quick shipping and good service.

It's one of our favorite tools : ) Enjoy, Matt. Thanks for shopping with us.
Awesome tool

Makes getting that perfect gap without pushing down on a table and measuring 10 times and especially if you have iridium plugs you dont wana chance gapping those without this tool!

Thanks, Kyle! We appreciate the great feedback. Thank you for shopping with us.

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