... valve. 1) quality garantee 2) specific certificate3) good quality and competetive priceRubber duckbill check valve size standards:Mounting dimensions flange ... : the design life of two years, but in general, at room temperature, and the climate is bad, you can use five ... Valve Advantage:1) Based on the difference in water pressure automatically turn on and off, safe and reliable, no noise, no need for ...