Parlec C50-30TT5 Tapping Heads; Shank Type: Taper Shank; Shank Diameter (Inch): 3; Taper Size: CAT50; Minimum Tap Capacity (mm): M20; Minimum Tap Capacity (Inch): 13/16; Maximum Aluminum Tap Capacity (mm): M33; Maximum Aluminum Tap Capacity (Inch): 1