Insteon 2441V Insteon and Totaline/Ventstar Compatible Thermostat Adapter Save energy and money on bills by remotely controlling your thermostat Compatible with Totaline/Venstar T1700, T1800, and T1900 thermostats No batteries! Insteon Adapter is powered by thermostat Award-winning Insteon technology provides superior performance and reliability At least one Access Point is required to communicate with your plug-in or wire-in Insteon-compatible devices.