The Holman Electronic 2 Dial Tap Timer is an easy to program tap timer. Programming is as easy as selecting the watering run time (up to 240 minutes) and the watering interval (from every 6 hours to every 7th day). The tap timer clicks onto a standard garden tap and is ideal for monitoring the watering of pots, hanging baskets, shrub areas, flower beds and small lawns. It is battery operated (9V) and features low energy use with patented eco-friendly battery life monitoring and LED flash display.