Product Specifications: Hot tub filter replacement PWW35L Length 8 1/2", OD 5", Top: Handle; Bottom Opening: 2",with SAE Thread, and 35 sq. ft. spa filter. Replacement Model: Compatible with PWW35L, for Unicel 4CH-935,for Filbur FC-0170,for PDC580-AFS, SD-01235, 817-4035 hot tub filters. Note: This is the information of compatible models.NOTE: These are compatible spare parts, manufacturer names and part numbers are for reference only. Hrozny is an independent brand. High Efficiency Filtration Performance: The special filtration structure of this spa filter has a 21-10% higher filtration capacity than the ordinary point-bonded structure, which can capture impurities more effectively and improve cleaning efficiency. Easy to Clean: This spa filter adopts an advanced three-leaf fabric structure, which is easier to clean impurities. For a better experience and effect, it is recommended to clean it every two weeks. Strong Durability: Spa filter for hot tub use reusable filter media, anti-break end caps and sturdy center support, which can effectively extend the service life of the pool filter cartridge and reduce the frequency of replacement. This hot tub filter replacement for PWW35L is 8 1/2" in length, 5" in outer diameter, top: handle; bottom opening: 2", with SAE thread, 35 sq ft spa filter. Replacement Model: Compatible with PWW35L,for Unicel 4CH-935,for Filbur FC-0170, PDC580-AFS, SD-01235, 817-4035 hot tub filters. Note: This is the information of compatible models. With high efficiency filtration performance and easy-to-clean design, and durable, it can effectively extend the service life of the filter element.