Engine Tools · M120040-C
1/2 Inch Drive Spark Plug Socket 16-21mm
Metric Spark Plug Removal Tool Sold Individually · Choose Your Size
Pair it with
This item: 1/2 Inch Drive Spark Plug Socket 16-21mm (16mm)
$5.99
5-Piece Flat and Phillips Screwdriver Set
$64.99
Recommended for diesel and heavy equipment work
- Fast US dispatch from our Fort Worth, Texas warehouse
- Genuine Teng Tools — professional-grade, designed in Sweden
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- Backed by guarantee — built to last a working lifetime
Why this one
1/2 inch drive leverage
The 1/2 inch drive connects to your ratchets, breaker bars and torque wrenches, with more leverage than smaller drives on plugs seized by heat cycling.
Plug retention
The 16 mm size has a rubber insert that holds the spark plug securely during installation and removal.
Sizes 16, 18 and 21 mm
Sold individually in 16, 18 and 21 mm, so you only buy the size your engine needs.
Controlled force
It delivers controlled, even force to the plug hex for routine maintenance or an engine rebuild.
Read the full description
When your engine calls for a 21 mm plug, having the right tool on hand saves time and prevents damage. This Teng Tools 21 mm socket is built around a 1/2 inch drive square, connecting to the ratchets, breaker bars, and torque wrenches you already rely on every day.
The larger 1/2 inch drive provides more leverage than smaller-drive alternatives, which matters when plugs are seized from heat cycling or installed at higher torque values. Whether you are performing routine maintenance or tackling a more involved engine rebuild, this tool delivers controlled, even force to the plug hex.
Sold individually, this socket lets you buy exactly the size you need. Many kits on the market bundle SAE and metric sizes together, but if your vehicle only requires 21 mm, there is no reason to pay for five sockets when one will do. Add it to your existing Teng Tools collection or start building a set one size at a time.
Teng Tools designs every product for professional use, so you can count on a precise fit and dependable performance across repeated service intervals. Keep this 21 mm socket in your toolbox and reach for it whenever the job calls for a metric plug change.
Get it in a set
This engine tools also comes in these 4 sets, with the tools that go with it.
Specifications
| Type | Auto Tools |
|---|---|
| Category | Engine Tools |
| Drive size | 1/2" |
| Part number | M120040-C |
Data sheet
Full details from Teng Tools. Download PDF
Lifetime warranty
Send a photo and your order number. Same-day shipping on replacements.
Ships from Texas
From our Fort Worth warehouse.
Questions?
Call (817) 767-3392.
Shipping
Free shipping on orders over $99. Orders are stocked, picked and shipped from our warehouse in Fort Worth, Texas — orders placed on business days ship same-day wherever possible.
Lifetime warranty
Teng Tools hand tools are backed by a lifetime warranty against manufacturing defects. Screwdriver bits and socket bits are consumables and are guaranteed to meet dimensional standards. Torque wrenches and air tools can be serviced and recalibrated on request — contact us to arrange it.
Returns
Not right for the job? Contact us within 30 days of delivery and we'll sort out a return or exchange. Tools must be unused and in their original packaging. Warranty claims are handled separately — a defective tool is our problem, not yours.
Why Teng Tools?
Swedish Design Since 1985
Trusted in 30+ countries. Designed in Sweden, built to ISO and DIN standards.
Shipped Fast from Texas
US warehouse in Fort Worth, so orders move fast. TAA approved for government and defense.
Lifetime Warranty
Something goes wrong? Send a photo and your order number — same-day shipping on replacements.
The Devil Is in the Detail
Satin-finish wrenches, through-blade screwdrivers, heavy-gauge storage — built to last.



