The Hayward DEX2420Z8A Air Relief Valve O-Ring Kit is an essential maintenance component designed for use with DE (Diatomaceous Earth) and Cartridge filters. This kit includes high-quality rubber O-rings specifically crafted to ensure a secure and leak-proof seal in air relief valves. The primary function of the O-rings is to prevent air and water leaks during the operation of the fil... https://www.usapoolshop.com/dex2420z8a-hayward-air-relief-valve-o-ring-kit