I've been using them for years, very handy to water multiple zones during the night, and be finished by the time I get up in the morning. Caution: The battery in the back yard timer died while the water was running, and it ran all night. Very green grass, slightly inflated water bill. Keep the batteries fresh. Another caution: I started having trouble with the back yard faucet, turns out Watts advises against using such devices on some of their freeze-resistant faucets. Can't really think of a reason, and it didn't elaborate, but the manual said it's bad for them to remain open for extended periods of time when the water isn't flowing. Replaced the washer in it last year, and it's been working fine ever since.