What type of batteries does the e7w Thermostat use and how do I install them?

The e7w uses four AA alkaline batteries (1.5VDC each) providing 6VDC total power. Insert the batteries into the battery compartment, matching the '+' terminals on the batteries to the '+' symbols in the battery compartment. Use only alkaline batteries, and dispose of used batteries according to WEEE Directive 2012/19/EC instructions. (Page 28-29)