The SFL50-5-13OBE from FilterLogic offers an economical and energy efficient alternative to your spa manufacturer’s original replacement filters. Please remember; it is recommended that you rotate filter sets every two weeks, each filter will last up to six months. It is important to keep well maintained filtration in your hot tub or spa. Not doing so may not cause damage to the integral pumps in your tub. Replacement of filters will also help to prevent the build up of sludge that can potentially lead to microbiological contamination whilst removing precipitated iron, calcium, body oils, lotions and dirt. This filter is compatible with a large number of filters from different manufacturers, this is why you should always compare the dimensions of your filter against the dimensions listed. Compatible with the following filters / systems: - Pleatco: PRB50, PRB50IN, PRB-50, PRB50-IN, PRB 50 - Darlly: 40506, SC706 - Filbur: FC-2390, FC 2390 - Unicel: C-4950, C4950 Dimensions: Length - 337mm Outer Diameter - 127mm Inner Diameter - 51mm End Cap Fitting: OBE (Open Both Ends) This filter will fit some of the models from the following manufacturers, please check dimensions: Aegean Spas Alps Spas Apollo Spas Aqua Leisure Aqua Spas Arctic Spas Astro Spas Baja Spas Barrier Reef Spas Beachcomber Spas Cal Spas Caldera Spas Canadian Spas Coast Spas Coleman Spas Coyote Crystal Water Spas Dakota Spas Dynasty Spas Elite Spas Emerald Spas Hollywood Hydro Pool Spas Hydro Spas Pacific Spas Pentair Dynamic Series Sierra Spas Waterway Spas