*Money Saving 3-Pack* When you order this product, you will save $3.00 off of the normal retail filter price. You will receive 3 genuine Unicel replacement filter cartridges. This 3 ounce filter has a closed top and an open bottom with 158 pleats. It is rated for 35 square feet. The Unicel spa filter cartridge should be inspected monthly and replaced every six to eight months if the spa is maintained properly. Note: this filter has been upgraded, it was originally for 25 square feet with 115 pleats. Save $3.00 when you order the 3-Pack.