16 mm spark plug wrench (China). It is used to remove and install the spark plug in the cylinder head: the 16 mm size matches the hex of the plug.
Suitable for spark plugs with a 16 mm hex. Thread the plug in by hand until it stops, then tighten it with the wrench without jerking, so you do not strip the thread in the head. Thread the plug in by hand until it stops, then tighten it with the wrench without excessive force so you do not strip the thread.
