The Shockwave Lineman's 3/8" to 1/2" 12PT 2-in-1 Socket is design to increase efficiency and safety for Lineman. With an anti-rust stainless steel spring loaded design, it is the most durable 2-in-1 socket design and provides hands-free changes. The 12PT design will fit all 3/8" and 1/2"" hex and square hardware for increased versatility. A 7/16" to 1/2" impact adapter is included