Review on Quick Connect Fitting Connection by YZM by Shane Jenkins

Obviously JohnGuest style nameless fakes but so far they work well. The tube will make a noticeable "step" when you insert it properly. My guess is that people who spot leaks only superficially squeeze the fitting - you really need to make sure it's fully inserted through the tight seal. Still use genuine JohnGuest valves for things that are under 7/24 pressure, but the price keeps going up. This is a good alternative to try.