This 24V 40VA transformer ensures effortless compatibility with popular smart home devices like Nest, Ecobee, and Sensi thermostats. Say goodbye to compatibility concerns as you power your smart doorbells and thermostats with ease using this versatile 24V doorbell transformer. Engineered for consistent performance, this transformer provides a stable 24-volt power supply to your devices, ensuring they operate efficiently round the clock. Whether you're installing a Nest doorbell or a Ring Doorbell Pro 2, this transformer delivers the necessary power without fail. Compatible with Nest, Ecobee, Sensi, Honeywell Thermostat, Nest Doorbell and All Versions of Ring Doorbell. 4"x4" Mounting Plate, Input: 120V AC; Output: 24V AC; 40VA, UL Listed.