*Money Saving 3-Pack* When you order this product, you will save $1.50 off of the normal retail filter price. You will receive 3 genuine Unicel replacement filter cartridges. This in-line filter has an open top and an open bottom with 103 pleats. It is rated for 25 square feet. The Unicel spa filter cartridge should be inspected monthly and replaced every six to eight months if the spa is maintained properly. Save $1.50 when you order the 3-Pack.