Built to Fit: PRB35-IN hot tub filter cartridge compatible with Rainbow Dynamic 35, replaces Filbur FC-2385, Pleatco PRB35-IN, Unicel C-4335, Guardian 409-219, Waterway Plastics 817-3501, Pentair R173431. Filter Dimensions: Length: 9 1/4"; 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 PRB35-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 Fil-fresh PRB35-IN hot tub filter cartridge, designed to work with Rainbow Dynamic 35 and Waterway 35 In-Line systems, and compatible with spas such as Sundance and Coleman. It replaces cartridge models including Filbur FC-2385, Pleatco PRB35-IN, Unicel C-4335, Guardian 409-219, Waterway Plastics 817-3501, Pentair R173431, Aladdin 13501, SD-00198, 03FIL1300, 17-2482, 25393, 303557, Darlly 40353, Magnum RD35, Baleen AK-3015, 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.