The P.S.S. (Packless Sealing System) shaft seal is a mechanical face seal that replaces the packing gland. The P.S.S. is the number one selling brand on the world market and is installed by production builders and the USCG as standard equipment. The dripless operation of the P.S.S. eliminates needless bilge pumping and minimizes corrosion. Reduces maintenance, ending the need to adjust packing or replace shaft damage due to the packing gland. Need to know both shaft and stern tube (shaft log) diameters to order.