Seal type : Self sealing valve guarantee quick isolation of SF6 gas.1) Metal to Metal seal - Convex surface and groove surface guarantee perfect tightness2) Soft seal â EPDM O-ring seals are perfectly work for gas filling system. Nominal size : 8mm(DN8) and 20mm(DN20). Maximum pressure : 64kgf/cm (PN64). High performance seals : EPDM (-60C~60C). Perfect pressure and vacuum tight.. All parts are available in Brass, Stainless steel, Aluminum. 100% tested before shipment.Seal type : Self sealing valve guarantee quick isolation of SF6 gas.