For re Seating most taps available on the U.K. market. The four plastic threaded guides are designed to fit taps to BS1010 with 18tpi threads and BS 5412 with BSP threads. Tool is Supplied with three zinc plated hardened steel cutters which will repair most popular 12mm (1/2") and 19mm (3/4") taps. Features and BenefitsCutter sizes: 17mm dia. (for some 12mm taps; 19mm dia. (for some 12mm taps); 25mm dia. (for some 19mm taps) Contents 1 x Cutter: 17mm (11/16") dia. suitable for some 12mm (1/2") taps 1 x Cutter: 19mm (3/4") dia. suitable for some 12mm (1/2") taps 1 x Cutter: 25mm (1") dia. suitable for some 19mm (3/4") taps