I had to replace my original valve that was platic and the back flow preventer ball was not doing its job. Delivery was quick and would recommend others to use this valve.
I was a little apprehensive about the spring tension in this device. I was installing it between the fresh water tank and the pump. The pump was allowing water to pass from "City water" connection to the fresh water tank. I was concerned that the pump suction may not overcome the spring tension. As it turned out it was not a problem. The valve worked perfectly.
WARNING: This product can expose you to chemicals, which is known to the State of California to cause cancer and reproductive harm. For more information, go to www.P65Warnings.ca.gov.