Built to Fit: PRB25-IN hot tub filter cartridge replacement for Pleatco PRB25-IN, Unicel C-4326, Filbur FC-2375, FC-2370, Guardian 413-106, 3005845, 17-2327. Filter Dimensions: Length: 13-5/16"; Outside Diameter: 5"; Top & Bottom Openings: 2-1/8" 3X More Effective Filtration: NSF 50 certified and designed with ultrafine particle technology to capture 3× more debris than standard filters, effectively trapping leaves, hair, sand, oily residue, and sediment for crystal-clear water Built to Last: Our PRB25-IN spa filter replacement features corrosion-resistant end caps that withstand chemicals and harsh conditions without melting or degrading. Reinforced pleated fibers resist deformation, ensuring consistent, reliable performance Washable & Reusable: The advanced trilobal structure prevents large particles from entering, ensures even debris distribution and prevents clogs—promoting quicker and easier rinsing to reduce cleaning time Less Frequent Cleaning: The free-flow core allows for better water circulation and reduces clogging, extending the time between cleanings. What once required bi-weekly maintenance now only needs attention once a month Enjoy crystal-clear spa water with the Fil-fresh PRB25 hot tub filter cartridge, seamlessly replaces PRB25-IN, Unicel C-4326, Filbur FC-2375, FC-2370, SD-00196, 303909, M-4326, 8172500, R173429, and more. Made from premium trilobal polyester, this high-efficiency spa filter captures hair, leaves, dust, and sediment with ease. A quick rinse once a month keeps it working like new, so your spa stays fresh, clean, and always ready for relaxation with less maintenance.