General description A 23-piece tap and die set, suitable for cleaning and repairing Whitworth (BSW) threads ranging from 1/8"-40BSW to 1/2"-12BSW. Whitworth threads are commonly found in classic cars and use a different measuring system from AF or metric equivalents. Technical specifications Material: Carbon Steel Number of pieces: 23 Sizes of Dies: 1/8"-40BSW, 3/16"-24BSW, 1/4"-20BSW, 5/16"-18BSW, 3/8"-16BSW, 7/16"-14BSW, 1/2"-12BSW Sizes of Taps (taper & plug): 1/8"-40BSW, 3/16"-24BSW, 1/4"-20BSW, 5/16"-18BSW, 3/8"-16BSW, 7/16"-14BSW, 1/2"-12BSW Compatibility and accessories Includes a die wrench Includes an adjustable tap holder Usage For use on classic British cars and motorcycles. Other information Supplied in a metal storage case.