Compatibility: Compatible with for standard spring check valve models 7235, 7236, 7305, 7511, 7512; Please note: Not compatible with Large Check Valve 7307, Not compatible with 263042 Check Valve, please confirm your spring check valve model before purchasing Pool Check Valve Cover: Includes P: #7451 flapper, 7302 anti rust spring, 7304 pin, 7236 cover, and # 1132 cover rubber flange O ring Working Principle: This transparent check valve cover is equipped with a spring loaded sealing baffle, the pressure of the pool water open the valve flap, allowing the water to flow smoothly through the valve body into the underground swimming pool, this design can effectively prevent the liquid from flowing backward, to that the pool water supply stability and safety Material Upgrade: our pool check valve cover baffle end face is made of rubber, resistance, and good sealing; The spring and pin are made of upgraded stainless steel so that the spring tension is stronger and , not easy to rust; Strengthen the structure of the cover, crack , high strength, transparent, not easy to scratch, not be yellowed and fuzzy, long service life, is a good accessory for the maintenance of the swimming pool in the summer Note: Please check if it matches your model before purchase Colour:Photo Color Material:plastic Package Contents: 1 set x Check Valve Covers Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.