"OK solid check valves, but the rather small flat areas on the barrel sides are not the best I have used for getting a grip on with a spanner or wrench when tightening the compression joints. Aok once fitted."
"The valve body is too thin, the ball valve distorts when tightening with spanner, with only a moderate ammount of force. You end up gently squeezing the body with a set of mole grips to reseat the plastic ball inside, its not much, but you can blow through the valve. Once fixed onto the pipework, its a bit of a gamble weather to give it that extra "nip" up."