If you have trouble getting your taps to start off square in the pilot hole then this device could be for you. The tap wrench, which will handle from 2.5mm to 6mm square, locates in a sleeve with a 40mm diameter base machined square to the bore to ensure perfect alignment. There is a triangular groove cut across the base for accurate tapping into circular bars or tubes. Two apertures in the side of the sleeve allow you to check the progress of the tap.