This Replacement filter complies with the technical specifications as Unicel # C-4305, Pleatco # PMT50, Filbur # FC-1617 and OEM # 220142. This filter cartridge is capable of handling the top load of 50 square feet and best fit for Cal Spas, Martec, Sonfarrel, Advantage Mfg., Pageant Spa, Dolphin Spas, Jacuzzi Spa Div./Jacuzzi Bra, Sundance Spas. With its 14 7/8 inch length and 4 15/16 inch width, this filter cartridge provides you complete protection from all kinds of debris in your pools and spas. Very easy to install this filter cartridge is made of high quality of materials.