The Hayward CX120D O-Ring is a high-quality replacement part specifically designed for Hayward Micro Star-Clear Cartridge Filters. This O-Ring plays a crucial role in maintaining the efficient operation of your pool's filtration system. With a precise fit, featuring an inner diameter of 5-7/8" and an outer diameter of 6-1/4" , the O-Ring ensures a tight seal between the filter head an... https://www.usapoolshop.com/cx120d-hayward-o-ring-for-hayward-micro-star-clear-cartridge-filter