... type: type A, type B, type C, hi-low, double thread and other special threadLength of screw: 150 to 300mmDiameter of ... , Pozi, Philips, Square, HWF undercut, HWH, serration, flower head and othersPlating: plain, yellow zinc, zinc, black phosphated, gray phosphated, black ... : in bulk, standard packing for exportThey have good quality, and reasonable price Hexagon Wafer Head Self Tapping Screw