The Klein Tools 4-in-1 Square Impact Socket, No. NRHD4, is an single-ended impact socket with hands-free adjustment between socket sizes to help provide efficiency on the job. This socket includes 3/4", 13/16", 1" and 1-1/8" square sockets and an additional 7/16" hex quick-change adapter. NRHD4 fits 1/2", 5/8" and 3/4" pole hardware. This socket is engineered for use with impact drivers.