Spark plug wrench for 4-stroke engines. It lets you remove and install the spark plug in the cylinder head.
Choose by the size of the hex on the spark plug. Tighten carefully: the thread in an aluminum head is delicate. Before installing, check the electrode gap and compare it with the engine manufacturer's recommendation. Thread the spark plug in by hand until it stops, then tighten it with the wrench without excessive force so as not to strip the thread.
