Review on Pack of 2 - EVIL ENERGY 5/32" 4mm Silver Aluminium One Way Fuel Line Check Valve, Non Return Diesel by Faliere Jorge

Quality construction, beautifully engraved arrow showing direction of flow. Requires VERY low cracking pressure but absolutely no back flow. it was extremely important for my application. I added a couple of these to my welder with some tees so I can add helium to my argon and argon/CO2 mixes for welding thicker aluminum and MIG stainless steel respectively. Check valves allow helium flow in only one direction and prevent cross-contamination of argon and argon/CO2. Welding gas normally flows at VERY low pressure. They measure in cubic feet per hour, not PSI. Even if I only need to refill a little helium, these valves open immediately and do not interfere with any noticeable flow. I can still get the stable, predictable flow I need for a good gas mix. When the helium tank is not connected I can leave this port fully open and absolutely NO argon or argon/CO2 will flow back and forth through the check valves. With an application like this (especially considering how long it took to install) I really didn't want to risk either of them leaking and having to be replaced on the go, or the plastic nipple snapping when I crank the hose clamp. It was the right choice. Note, however, that the nipples are 1/4" OD, not ID. Check your application carefully before purchasing!