The Orbit Thermostat 83521 is a programmable thermostat designed for clear and easy-to-read comfort control. With a 7-day programming schedule and 4-wire wire configuration, this rectangular-shaped thermostat allows for efficient heating and cooling adjustments. The digital display and dial control style make it user-friendly, while the low voltage operation ensures energy conservation. Compatible with various systems and powered by AAA batteries, the Orbit Thermostat 83521 is a reliable and convenient choice for home temperature management.