Safety Technology International, Inc. STI-3350 Wireless Doorbell Chime (or assistance call button or receptionist call button) with Receiver, Part of Musical Wireless Chime Series Easy to install no expensive through-the-wall drilling 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.