This adapter's patented motion-detecting sensor lets you control a household sink faucet with a mere wave of the hands, avoiding the cross-contamination common with faucets in busy households. The infrared sensor starts water flow as soon as it detects movement, eliminating the spread of germs on handles and facilitating work in the kitchen when both hands are full or dirty; the flow stops as soon as hands move away (or after one minute), conserving water. The device requires no professional installation because it simply screws into the aerator of the existing faucet neck. Its unique side-mounting design won't take up valuable working space in the sink. When a steady stream of water is required, an override button keeps the water running f or three minutes. The sensor runs up to 1 1/2 years on four AAA batteries (not included). 4" H x 2 1/4" W x 4 1/4" L. (8 oz.)