Details: This cartridge is designed to use with Pentair pool and spa Dynamic Series II top load high flow cartridge filter model RTL 25. This cartridges are manufactured of the finest quality filter media. Use for spas, hot tubs, and swimming pools. Comes with 8-1/4-inch diameter, 18-inch height, 2-inch plumbing size socket and 25 square feet cartridge filtration area. Measures 4-inch length by 5-inch height by 4-inch width.