Honeywell ERM5220R1018/U -RedLINK Equipment Remote ModuleThe Honeywell ERM is like a new cordless tool in your toolbox. Pull it out when it's too costly or time consuming to run wires from a condensing unit or boiler to control devices. There are fewer holes to drill and wires to run. Just faster, easier installation that gives you more profit per job. Make the Honeywell ERM your go-to choice for fast, easy equipment installation.Features Wireless Relink communication between condensing unit/compressor or boiler and thermostat Eliminates the need to run additional wires to your equipment, for example, during a heat pump upgrade Suitable for outdoor use Temperature sensor terminals for outdoor temp sensors or indoor freeze protection LEDs for easy installation checkout May reduce damage to homes since wiring/drilling is eliminated