Outer Diameter: 4 15/16" Length: 13 5/16" Media: 25 SF Compatible with Pleatco PRB25-IN Unicel C-4326 Filbur FC-2375 Pentair 17-2327 Jacuzzi Premium 373045 Tier1 PAS-1438 Rainbow Plastics 17-2327 Beachcomber 3005845 Waterway Plastics 817-2500 Hot Tub Spa Filter. SpiroPure pool and spa filter cartridges offer long-lasting, durable filter media with high dirt holding capacity for clear, sparkling water in your pool or hot tub spa. A strong inner core means increased strength without hindering water flow or filtration performance. Easy to install, durable filter cartridges that allow for high filtration performance and efficiency SpiroPure SP-PS-2375 Hottub Spa Pool Filter Replacement Cartridge. Easy to install, durable filter cartridges that allow for high filtration performance and efficiency