Constructed of the same tough CPVC material used on the NeverLube. The Check Valve's clear lid and red seal plate let you easily see and access debris. It features a unique swing/spring design for both return and intake water. The diverter swings completely open with minimal back pressure and no water turbulence. Minimal hydraulic loss. Clear lid for easy inspection. Easy to disassemble when clearing debris. Corrosion resistant stainless steel swing. Highly resistant to Chlorine.