I'm working on finding a dependable . 5 gpm flow switch. The switch on the left started our working well after a few weeks it started sticking in the on position after the faucet was turned off. I replaced it with a new one, installed an isolation relay, same problem. The one on the right, Harwil Q-12N is a different style switch, same .5 gpm. I installed it yesterday, I'll see if it holds up better.