The First Company E137 Transformer is a 208–240V primary to 24V secondary HVAC transformer designed to provide reliable low-voltage power for control circuits. It operates by stepping down the higher supply voltage to 24V, which is suitable for low-voltage HVAC controls. The E137 is used with First Company fan-coil and air-handling equipment, supporting components such as thermostats,... https://www.partshnc.com/first-company-e137-transformer-208-240-24v