The MILWAUKEE 3/8in Drive 9/16in 6 Point Spark Plug Socket features a durable dual-material rubber retainer designed to maintain a more secure fit within the socket while securely holding onto spark plugs to avoid dropping or damaging. A precision knurling on the outside of the spark plug socket allows for better control when hand tightening or loosening. Both the socket and retainer withstand harsh chemicals commonly found in the garage. With stamped size markings, its easy to identify the size of the socket. The external hex at the base of the socket fits an 11/16in wrench for added control. Milwaukee Spark Plug Sockets are backed with a Lifetime Guarantee.