SIGNET Drive Plug 21mm Hex 65mm Overall Item 12241 3/8" Clip-Type Socket, Size, Length, No.

Drive size (DR): 3/8, Hex size (mm): 21, Overall length (mm): 65, Socket outer diameter (mm): 26, Drive part outer diameter (mm): 22, Weight (g): 143 The spark plug is held in place by a clip located inside the socket. No magnets are used, so iron dust won't stick to it. Electronic devices such as sensors are not affected by magnetic fields. Clip-on design. No worries about sensor interference or damage to the magnet itself, which are common issues with magnets, allowing for worry-free operation.