From inside (document excerpt):
RTH5100B Non-programmable Thermostat. Free Installation Instructions in PDF. The RTH5100B Thermostat provides electronic control of 24 Vac singlestage heating and cooling systems or 750 mV heating systems.
Contents
Prepare for Installation .. 3
Follow Important Instructions .. 5
Remove Old Thermostat … 6
Follow Special Instructions … 7
Label Old Thermostat Wires … 10
Mount New Wallplate to Wall .. 11
Connect Wires to New Wallplate .. 15
Install Batteries … 20
Attach New Thermostat to Wallplate … 21
Configure Installer Setup .. 22
Customer Assistance.. 28
Limited One-Year Warranty .. 29
Source: honeywell.com