Review on 💪 High-Performance RUSSELL 650603 Black Anodize Check Valve - 6an Male to 6an Male by Craig Pears

Well, first impressions aren't great. You can blow in any direction from the box. With my air compressor I shot air both ways and then the valve stopped flowing in the opposite direction so maybe that fixed the problem or it's working. Mouth blowing is very, very limiting though. I bought this valve and another brand that costs twice as much, the more expensive one has almost no restriction in which direction the flow should go and perfectly and quickly blocks the flow in the opposite direction. To be fair, it's a check valve. Designed more for liquids, I am testing it with air and plan to use vacuum/boost check valves for the crank vents or an upgraded PCV system to catch cans. UPR is a trademark of another product I purchased. I will return this one and buy more UPR. There aren't many great options for it, and I haven't seen a single review that focuses on this use. So hope this helps the next guy. Luckily the UPR has a 17mm OD inlet and outlet, not a style. But it costs extra $