Designed to operate with tank or tankless water heaters, the S3-100 from ACT, Inc./D’MAND Kontrols incorporates advanced on-demand technology into a home’s hot-water distribution system to provide complete control over when hot water is needed. It includes a three-speed high-performance stainless steel pump fastened to an electronic control box, and can be located at the hot-water heater on a dedicated return line. 800/200-1956; www.gothotwater.com.