DIG ECO1ASV.075 ECO1 ASV Single Station Ambient Light Powered Controller with 3/4" Anti-Siphon Valve Environmentally friendly with no backup battery or AC power necessary; uses clean, renewable solar power Use for drip irrigation or sprinkler systems Seven buttons with integrated LCD Programmable run times from 1 to 5 hours and fifty nine minutes in 1 minute increments No backup battery or AC power necessary - uses clean solar energy