Safety Technology International, Inc. STI-3353 Wireless Chime Receiver,  Transmitters Sold Separately, Part of Musical Wireless Chime Series Receiver plugs into any standard 120 VAC outlet Operates up to 500' from transmitter Has a low and high volume adjustment on receiver Able to play 10 sounds UL & CUL Listed, FCC & IC Compliant. Limited one year warranty.