Feature: 1. Good Filtering: Can collect and remove debris and deposits from pools such as hair, leaves, dust, sediment, sand, etc. 2. Practical Uses: The good filtering effect ensure good water quality, suits for pump, swimming pool, spa pool and so on. 3. Quick neating: Scrub with a cartridge neating tool, then wash under strong water pressure to remove loose particles. 4. Good Materials: Combining premium polyurethane and non woven fabric materials, with 104mm OD, 52mm ID and 80mm height. 5. Including 4Pcs: There are 4pcs spa filter cartridge in the set, and it's recommended to replace every 2 weeks for use. Specification: Item Type: Spa Filter Cartridge Outer Diameter: Approx. 104mm / 4.09in Inner Diameter: Approx. 52mm / 2.05in Height: Approx. 80mm / 3.15in Material: Polyurethane, non woven fabric. Application: For pump pool, swimming pool, spa pool, etc. Package List: 4 x Spa Filter Cartridge