Horstmann HRT Series Mains Operated Electronic Room Thermostat offers the latest energy saving control technology combined with established Horstmann design and manufacturing expertise. This makes them suitable for use in most types of heating system that respond to a 230 volt mains electrical On/Off signal. Designed to look good, these thermostats will out perform many older styles of thermostat and can often produce savings in the order of 10% over and above those achieved by traditional units using older technology.