Heavy duty seal PS-3865 shaft seal assembly for salt water, viton salt & ozone shaft seal! this is an extra heavy duty shaft seal. Made with a carbon graphite, stainless seal and viton rubber. This is the longest lasting seal available and is designed for use with ozonators and salt chlorine generations as well as a regular pool and spa use. These applications require tough seals due to there more corrosive nature. the u.s. Seal PS-3865 is designed for pools and hot tubs that are using salt generators or ozonators. These applications require tough seals due to there more corrosive nature. 5/8" shaft and viton / graphitic plastic ss with polished ceramic seat. Industry standard for pool and spa applications with salt generators and ozone generators. replaces: u.s. Seal vg-1000 value u.s. Seal ps-1000 premium u.s. Seal ps-961 spas u.s. Seal ps-1905 silicone carbide aladdin as-1000 american products 397012 ampro-diaclear ap-304d anthony 04380 gecko aqua-flo 92500050 gecko aqua-flo 92509040 gecko aqua-flo 92500040 astral pool series 1600 doughboy 306-1002 jandy pb4-60 pentair 071734 premier 31-813 sta-rite u109-136ss waterway 319-3100b specifications shaft seal head typeb quality/materialbetter - viton carbon graphite shaft size5/8" seal outside diameter1-7/16"dia seal height25/32" mating ring diameter1-1/4"dia mating ring thickness13/32" Equipment, Pump Motors, Motor Seals.