This tap set is made of high speed steel and has a 0.255 inch, 0.318 inch, 0.381 inch, 0.323 inch, 0.367 inch diameter shank. It includes plugs, sizes ½"-13, ½"-20, ¼"-20, ¼"-28, ⅜"-16, ⅜"-24, 5/16"-18, 5/16"-24, 7/16"-14, 7/16"-20, and meets the standards for USCTI 302. This 303 series tap set has a bright (uncoated) finish, and has fractional inch measurements. It has right hand direction with a 2½ inch, 2 23/32 inch, 2 15/16 inch, 3 5/32 inch, 3⅜ inch length.