... kinds of cnc part 1)Features:1.Head type: flat/countersunk,slotted or as request2.Drive type: Phillips, Pozi, Square, Torx ... .) NameSlotted round head screw, slotted countersunk screw, slotted cap head screw, cross recessed screw, torx socket screw, set screw, machine screw, knurled screw, aluminum screw, wing screw,etc.Carbon steelMild/medium ...