selt-tapping screw: 1) Materials: carbon steel,copper 2) Size:it's up to client's requirements 3) Color:zinc plated,black selt-tapping screw:1) Materials: carbon steel,copper2) Size:it's up to client's requirements3) Color:zinc plated,black4)Head type:flat head,pan head,bugle head,truss head,hexagon head5)Recess:philips,slotted,cambo,square,six-lobe,pozi (its up to the clients requirement)6) ...