Genuine Aprilaire 120 volt, 50 watt current sensing relay. This relay will switch on a 120 vac load (50 watt max) when 4 amps of (blower motor) current is sensed. The pair of wires are 18 awg, length 32".
This 120 volt relay is for turning on a 120 vac load such as an electronic air cleaner, the 120 vac rating does not refer to the blower voltage. The blower voltage can be 120v or 240v as only the current is sensed. The need to wrap the blower wire around the RP-51 is typical, see instructions.