3/8"SD Magnetic Spark Plug Sockets from Britool Hallmark 16mm & 21mm

The Britool Hallmark 3/8" drive spark plug socket is designed for precision, durability, and ease of use in automotive applications. With an approximate length of 65mm, it provides the ideal balance between accessibility and control when working in engine bays.

Featuring an integrated magnetic insert, the socket securely retains the spark plug during removal and installation, reducing the risk of dropping or damaging components. The high polished chrome finish offers excellent corrosion resistance while maintaining a clean, professional appearance.

Stamped with the modern Britool Hallmark Marque of Skill branding, this socket reflects trusted quality and performance. 

Available in two metric sizes, 16mm and 21mm, to suit a range of spark plug applications.

The 16mm can be used with a 3/8" drive ratchet or 19mm spanner and is approximately 62mm in overall length.

The 21mm can be used with a 3/8" drive ratchet or 22mm spanner and is approximately 65mm in overall length.

Also available as a standard non-magnetic version is preferred - MSP

Please note that images are for illustrative purposes only and may show a different size than the item supplied.

The HALLMARK range was developed by Britool in the 80's for the automotive aftermarket. it has been the professional’s choice ever since. Each tool is marked with the Britool hallmark  your guarantee of quality.

The Britool Hallmark guarantee covers against defective materials and/or workmanship when used for the purpose for which they were designed and for the expected life of the tool. In the unlikely event that a product fails during normal use, it will be repaired or replaced. The guarantee does not extend to fair wear & tear, moving parts such as ratchet mechanisms or consumable items such as bits and repair kits.