Never wait for hot water again. The Watts Heat H2O Hot Water Recirculation System utilizes thermal bypass technology to provide hot water to your faucet or shower instantly. The device uses the pump at the water heater and a patented under-sink, thermostatically controlled sensor valve to create a pressure differential, allowing cool and cold water to bypass into the cold water supply line at a low volume and keeping the water in the hot water supply line at a no-wait temperature throughout your entire home. Easily installed into existing plumbing without the need for a return line or additional electricity under the sink, this quiet, efficient system requires no maintenance once installed and includes everything you need for quick DIY installation: pump with 10 ft cord, 2 adapters with rubber washers, sensor valve, mounting screws, and two 12-inch supply lines. With Watts Heat H2O Hot Water Recirculation System, your days of wasting time, water, and money are over. Readily available hot water means no need to let the tap run while waiting for it to heat up, which leads to significant water and money savings: up to 12,000 gallons per year and up to 10% off your water bill! This pump also includes a convenient built-in programmable timer that can be set to run for 24 hours a day or to activate only during peak use times. Its 24-hour dial features quarter-hour division tabs and AM/PM indications so you can easily set operation of the circulator according to your household's water usage patterns. Not designed for tankless water heaters. For indoor use only.