The Hayward CX800C Filter Head Cover with Air Relief Valve is an essential component for Star-Clear II cartridge filters. This filter head cover is a high-quality replacement item that will improve longevity of your filtration system. With a diameter of 10-3/4", it fits snugly over the filter, creating a tight seal to prevent leaks and ensure efficient performance. The inbuilt air rel... https://www.usapoolshop.com/cx800c-hayward-filter-head-cover-w-air-relief-valve