The contractor's non-programmable thermostat choice for 1H or 2H/1C heat pumps with option to mount horizontally or vertically. Easy installation, easy to view large back-lit display, adjustable compressor delay and emergency heat-mode switch. Additional features include user temperature calibration in both Fahrenheit or Celsius, adjustable 9-step temperature swing and high and low limits. Dual powered 24 VAC or (2AA) Alkaline Batteries (included) with low battery indicator. Compatible with most 24V heat pump systems, 1 or 2 stage heat/ 1 stage cool heat pumps. Not compatible with multi-stage gas or oil furnaces, hydronic hot water systems, 120/240V line voltage systems (without transformer), conventional (non-heat pump) systems. 5 year limited warranty.