BackPlugs for oil ducts and vent holes Up to 400 MPa (58 000 psi) SKF plugs are designed to seal oil connections at maximum pressures of 400 MPa (58 000 psi). The following plugs are available: 233950 E with G 1/4 thread 729944 E with G 1/2 thread 1030816 E with G 3/4 thread