“Quality inline check valve,better than others seen,because of the low to high pressure rating.It does have an arrow for flow direction.I will be using two of these inline check valves on separate airlines into a tee piece,to increase the CFM, by using two air compressors together for spray painting.These check valves prevent air flowing back down the line(s),a must have when running two compressors.Highly recommended product-AAA+++”
