Programmable thermostat provides electronic control of 24 vat conventional and heat pump systems | heat pump - 2-heat, 1-cool 1st stage heat - heat pump 2nd stage heat - auxiliary heat 1st stage cool - 1st stage cooling | clear standard display with backlighting | 5 - 1 - 1 or 5 - 2 day programming | power source - hardwire, battery (alkaline batteries included) | easy change battery door | adjustable temperature differential | adaptive intelligent recovery | temperature range stops | electrical rating: 20-30vac | the focuser programmable thermostat provides electronic control of 24 vat conventional and heat pump systems or 750 MV heating systems. If used as directed, programmable thermostats can save up to 33percent on annual heating and cooling costs (Savings may vary)