... of bolts( hexagon head bolts, coach bolts, carriage bolts, hanger bolts, etc ), kinds of screws( self-drilling screws, lag screws, chipboard screws, drywall screws, wood screws, etc.), kinds ... treatment is white zinc plated, yellow zinc plated, black zinc plated, black phosphatization finishing, grey phosphatization finishing, brass plated, nickel plating, hot dipping, machinery zinc plated, etc. We ...