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Angled view of a silver deep-well spark plug socket showing square drive recess, hex internal opening, knurled band and embossed logo.Side view into the open end of a silver spark plug socket revealing a brass-colored retaining ring and six-lobed internal hex profile.Top view into a deep-well spark plug socket showing six-lobed hex interior, brass-colored retainer ring and central sleeve.

3/8-Inch Drive Spark Plug Socket, 16mm, 6-Point Deep Well with Rubber Retainer

Professional-grade spark plug socket with internal rubber retainer, designed for precision engine work and bulk shop inventory.

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Description

3/8-Inch Drive Spark Plug Socket, 16mm, 6-Point Deep Well with Rubber Retainer

Brief Overview

This 3/8-inch drive spark plug socket delivers the precision and durability that professional mechanics expect from daily workshop use. The deep-well design accommodates longer spark plugs without obstruction, while the internal rubber retainer securely grips the spark plug during installation and removal—eliminating dropped plugs and reducing rework. For shops stocking multiple spark plug sizes, this socket pairs naturally with magnetic-insert spark plug sockets for enhanced retention on harder-to-access plugs.

Key Features

  • 6-Point Hex Design: Engages spark plug terminals with precision; reduces rounding and damage to plug electrodes.
  • Internal Rubber Retainer Ring: Brass-colored metal ring with cushioning insert keeps spark plugs secure during insertion and removal.
  • Deep-Well Construction: Extended 65mm length provides clearance on engines with tight valve covers or aftermarket components.
  • Knurled Grip Band: Machined knurling near the drive end improves handling and reduces hand fatigue during repetitive work.
  • Standard 3/8" Square Drive: Compatible with all 3/8-inch ratchets, extensions, and pneumatic tools.
  • Machined Steel Body: Uniform silver finish with durable construction for years of reliable service.

Technical Specifications

Size (mm) Outer Diameter D1 (mm) Inner Bore D2 (mm) Overall Length (mm)
16 22 18.8 65
18 26 20.4 65
21 28 21.5 65

Business Advantages for Resellers

High-Turnover Item: Spark plug sockets are consumable-adjacent tools—customers purchase them regularly as replacements or to build tool collections. The three-size range (16mm, 18mm, 21mm) covers the majority of automotive applications, making this a multi-unit SKU opportunity.

Margin Protection: Rubber-retainer spark plug sockets command a price premium over basic sockets. The retainer eliminates customer frustration and callbacks, reducing your service liability and boosting customer satisfaction ratings.

Bulk Order Economics: Stock all three sizes as a kit or individual SKUs. Garages, fleet maintenance shops, and independent mechanics buy in quantity. Competitive pricing per unit scales significantly with order volume.

Low Support Risk: This is a passive accessory with no moving parts or power requirements. No warranty complications or technical support burden.

Recommended Applications

  • Small-Engine Spark Plug Installation: Lawnmowers, pressure washers, chainsaws, and portable generators.
  • Automotive Engine Service: Gasoline cars, motorcycles, ATVs, and light-duty trucks.
  • Fleet Maintenance: High-volume shops performing routine spark plug replacements on multiple vehicles daily.
  • DIY and Home Workshop: Accessible tool for non-professional technicians; retainer prevents frustration.

Why Choose This Socket Over Alternatives

The internal rubber retainer is the key differentiator. Without it, spark plugs—especially smaller 14mm and 16mm sizes—can fall out of the socket while reaching into tight engine bays, causing dropped plugs, wasted labor time, and frustrated customers. This socket eliminates that problem entirely.

The 6-point hex design also prevents cam-out damage to spark plug terminals, preserving the integrity of the ignition system and reducing the need for customer comebacks due to fouled or damaged plugs.

Stock all three sizes and position this as a must-have accessory in your spark plug and ignition category.