The MCU-21 is a controller and sensor in one and its revolutionary size (3-1/8" X 1-1/8" X 3/4") makes it super compact and easy to hide. It has all the features of large expensive systems that use bulky controllers and long wires and is simple to install at an economical price.  Note: Power must be located within 12 feet of the MCU-21 control/sensor or a 6' extension cable must be purchased separately. Does not include plumbing supplies.

There are no moving parts and maintenance is a breeze. Just periodically clean the probes. That's it. Proudly made in the USA by Aquility Systems, Inc.