M3 Thread, Round Head Enlarge M3S-1000 × CAD Model Download CAD File × Step File Download IGS File Download Add to Parts List Message Related Products Replacement O-Rings O-Ring seals in all available materials. Configure Here Overview Description: Round head stud with screwdriver slot and M3x0.5 external thread. Used in M3 series elbow and tee fittings with built-in barbs (M3LS and M3TS series). Note: There is no o-ring gland. The o-ring provided with the part rests just under the round head.