Product Description Low voltage t-stat, digital programmable, terminal designations r, rc, c, o/b, y, g, w, y2, w2, a, l, s1, s2, control range 40 to 99 f, stages 2 heat (1 hip), stages 2 cool, temp settings 4 per day, power method 24vac or battery, color white, height 4 9/16 in, width 6 in, depth 1 3/8 in, voltage 24 ac, programs 7 per week, display type touch screen, lcd, backlit, horizontal mounting, ambient temp range 0 to 120 f, ambient humidity range 5 to 90 %, use with 6wy20, 6wy21, g2997337, g2480667, includes subbase '. From the Manufacturer The TB8220 Commercial VisionPRO 8000 Touch screen Programmable Thermostat is an effortless, seven day programmable thermostat that provides universal system compatibility, precise comfort control and is easy to program. The TB8220 provides temperature control for gas, oil, electric and heat pumps for up to 2 heat, 2 cool systems.