... /gray phosphate or black oxide. 3) Fine or coarse thread 4) #6,#8,#10 thickness This is Sino-American ... the leading manufacturer of drywall screws in this area.Drywall screws1) Description: Phillips bugle head, coarse thread, fine thread2) Surface treatment ... other kinds of nails and screws,such as drywall screw,chipboard screw,self-tapping screw,self-drilling screw,common nails,concreate nails ...