Monument 173 Stiffnuts Pro Kit (10 Piece)Monument 173 has been especially designed for removing stiff backnuts from awkward placed taps and to make tap installation a more rapid process, this tool is for 1 2 inch. BSP and 3 4 inch. BSP taps. The Monument 170 tool stays in position on the tap tail so can be used with one hand and uses mechanical advantage of the thread of the tap tail to remove stiff nuts. Ideal for 1 2 inch and 3 4 inch BSP 25 mm 27 mm nuts 29 mm ribbed 32 mm nuts. The