Searching for water level switcher we reached sites with similar products & from there we're linked to yr e-mail.This switcher that we look for will be placed on non pressure solar systems & will control water inlet (open & close water inlet)as non pressure tanks shouldn't be filled up completely (till their top). Ideally it can work horizontally or vertically & has to be connected to 1/2" pipe diameter.what are the item you can suggest us? What they do operate? What is their price? Can you send them directly to us?