This Replacement filter cartridge has the technical specifications as Unicel # 8465, Pleatco # PWK45N, Filbur # FC-3960 and it complies with the OEM # 31114 specifications. With its 3 inch holes both top as well as bottom this filter cartridge handles the top load of 65 sq ft. It is the best fit for Hot Springs Spas, Watkins Mfg., Tiger River, Hot Spot. This 10 ½ inch long and 8 ½ inch wide filter cartridge provides you the clean and clear water for your pools and spas free from dust, sand and worms. It is very easy to install and made of top quality material.