Replacement Pool Filters: Pack of 6 C-4326 filter cartridges features 3-ounce basis weight and 25 square feet of media (106 pleats) that catch 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: 13-5/16 inches Pool and Spa Fitment: Compatible with Hot Springs Spas, Nordic Hot Tubs, Pentair Pool Products, Rainbow Plastics, Waterway Plastics, Custom Molded Products, Coleman Spas, Beachcomber, Jacuzzi Premium, and more