Replacement Pool Filter: C-4335 filter cartridge features 35 square feet (219 pleats) of 3-ounce basis weight media that catches debris and particles down to an average of 20 microns in size, keeping your hot tub water clear Optimal Debris Capture: Filter pool cartridge has sharp, uniform pleat folds that maximize water flow, minimize pressure loss, and allow full use of the pleat surface to hold more debris Filter Media: Constructed with 100-percent polyester Reemay material that balances dirt-holding capacity, cleanability and durability with excellent chemical resistance properties End Cap Features: End cap design includes a 2-1/8-inch ID and an open configuration for easy cartridge removal and replacement; Durable plastic resists damage from chemicals; OD: 4-15/16 inches, Length: 9-1/4 inches Pool and Spa Fitment: Compatible with Bullfrog Spas, Pentair Pool Products, Rainbow Plastics, Waterway Plastics, Custom Molded Products, Caldera Spas, Sunrise Spas, Sundance Spas, and more