The PRO programmable family of thermostats offers a basic thermostat with the benefits of energy savings. the PRO features an easy-to-read display and 5-2 day programming. Weekday/Weekend programming - 5-2 (Weekdays, Weekend) programming. Backlit digital display - both current and set temperatures are easy to read in various lighting conditions. Precise comfort control [1 F (0.5 C)] - maintains consistent comfort to the highest level of accuracy. Basic operation - easy-to-use slide switches allow you to select the heat or cool mode, and operate the fan. The PRO 4000 has built in instructions - simple, pull out instruction manual. Adaptive Intelligent Recovery- ensures programmed temperature is reached by programmed time.