Recess Type for Screws and Bolts, Hexagon Socket (HS), Combined (C), Slotted (S), Square (Q), Line (LR), Crossed (P), Stainless Steel, Mild Steel, Aluminum Alloy, Copper Alloy, Zinc (Z), Zinc Yellow Chromate (C), Nickel (N), Chromium (CR), Brass (BS), Black Zinc (BZ), Unichrome (blue zinc) (U), Black Oxide (BK), Silver (S), Head Type for Machine, Tapping & Tapping-title Screws and Bolts, Pan (P), Oval (O), Flat (F or K), Truss (T), Binding (B), Fillister (FM), Chess (C), Hex. Bolt (HB), Hex. Indent w/washer (HW), Hex. Indent w/o washer (H), Round Washer (PW or N), Nominal Dia., Pitch, Basic Size, Tolerance, Pan (P), Oval (O) / Flat (F or K), Truss (T), Binding (B)