Long Wireless Range: Operating range up to 120m in open area ensures you to hear the bell & answer the door in time. Never miss your guests! 38 Different Ringtones: Provide 36 kinds of beautiful music to choose with 3 levels of adjustable volume from 20db to 80db. Wide Compatibility: Can be widely used in homes, apartments, villas, shopping malls, hospitals, seniors & disabled use the doorbells as assisted living call pagers, & more! Easy Installation: Easily plug receiver into an electrical outlet (no batteries required for main receiver). The push button can be fixed to the doorframe with the attached adhesive tapes. The push button is rated IP65 weatherproof & acceptable for outdoor use. Type: one transmitter (remote control) + one receiver (sounder) Remote control power: