This Replacement filter cartridge replaces Unicel # C-4402 and Filbur # FC-3071 while complies with OEM # C4402 specifications. It is capable of handling the top load of 20 square foot and most suitable for Aqua Spa. This 9 ¾ inch long and 4 5/8 inch wide filter cartridge has molded cone handle on its top while 1 7/8 inch open hole at the bottom. This superior quality filter cartridge is very easy to replace and provides you complete protection from germs and sand in your spa.