This Hozelock tap mounted egg timer type watering controller does not require batteries or a power source and can be manually set for a period up to 120 minutes, after which it switches off the water supply. Simply set the duration by twisting the dial and it will start counting down. Ideal for use with a sprinkler, so that you never forget to switch it off. It is supplied with a choice of 21mm (1/2" BSP) or 26.5mm (¾" BSP) adaptors for connection to most garden taps. The Auto Off Controller is a versatile unit that can be used with Garden Sprinklers (up to 10 Bar) or low pressure micro irrigation watering (1.5 Bar). It could also be useful when filling a pond or paddling pool, to avoid wasting water.Features & Benefits:• Easy to set up• Simple mechanical dial to set watering duration• Select watering duration of up to 120 minutes• No batteries required