1/2" DR. Deep Hexagon Socket (16mm)

One honest note if that is your purpose. A dedicated spark plug socket has a rubber insert or a magnet inside it, which grips the plug's ceramic insulator so the plug lifts out with the socket instead of dropping back down the well, and which cushions the ceramic against cracking. This is a plain deep hex socket without that insert. It will undo and do up a 16mm plug perfectly well, but it will not hold the plug, and fishing a loosened plug out of a deep well with your fingers is awkward — worse, dropping one back down can chip the ceramic, and a cracked insulator causes a misfire that is then very hard to diagnose. If spark plugs are the main reason you are buying, tell us and we will point you at a proper plug socket instead.

For everything else, 16mm deep reaches M10 studs in some patterns, suspension and driveline fixings, agricultural and industrial machinery studs, and nuts recessed at the bottom of housings and counterbores.

The socket is drop forged from fine chrome vanadium with a matt chrome finish. Chrome vanadium is the standard hand socket alloy: chromium raises hardness and wear resistance so the internal hex keeps its sharp corners, vanadium refines the grain and adds the toughness that stops a hard socket being a brittle one.

The buyers are vehicle and motorcycle mechanics, engine tuning and servicing workshops, agricultural and plant fitters, machinery maintenance, and hardware dealers supplying garages.

Practical points. Use a standard socket wherever it will reach, because a shorter barrel is stiffer and better aligned on a tight fastener. Seat the socket fully before applying force. Spark plugs should be tightened to their torque figure rather than by feel, since over-tightening damages the thread in an aluminium head. And never use a chrome hand socket on an impact wrench — plated hardened chrome vanadium is brittle under hammering and can crack and throw fragments. Message us on WhatsApp for a price, and say if plugs are the job.