The Southwire Company 50 feet 18/7 Thermostat Wire is designed to be used in heating and air conditioning bell and alarm system controls. This cable is made of solid copper paralleled conductors that have been covered with a brown PVC jacket. Sunlight resistant from-20 degree Celsius up to 60 degree Celsius. Thermostat WireLow Voltage Control Cord150 VoltsRated -20°C to 60°CSunlight Resistant