The Lisle Corporation 5-pc Large Tap Socket Set, No. 71670, are designed to fit 5/8", 11/16", 3/4", 7/8", and 1" (16mm, 18mm, 22mm, and 25mm) taps manufactured to M.C.T.I. standards. The sockets are ideal for use in restricted areas where a T-handle won't fit.