More convenient operation of manual air conditioning and heating systems that are automatically controlled via Check Temp III. No more annoying on and off switching. In addition to displaying indoor and outdoor temperatures, Check Temp III also features a time and date display, a trip master function with up to 10 stages, and a high-resolution, dimmable dot-matrix display. The background lighting color can be freely selected from 4 basic tones (white, blue, red, green) and many intermediate shades, and can be continuously adjusted to match any instrument lighting.