Includes Three Sizes for Non M.T.C.I. Taps. Ideal for use in areas where a T-handle won’t fit. Set of 11 sockets fit all number and fractional taps through 1/2″ and 1/8″ NPT taps manufactured to M.C.T.I. standards. Also fits metric taps through 12mm manufactured to M.C.T.I. standards. #2+, #3+ and #6- sockets can be used on non M.C.T.I. taps. .