Long Range SignalThe penetrating wireless signal can be transmitted up to 300m in open space and long distance even with many obstacles (doors, walls). 36 Melodies and 4-Volume Levels36 CD quality ringtones are yours to choose from by pressing the button on the receiver, with 4 adjustable volume levels 25dB-85dB. Waterproof DoorbellThe superior material transmitter button is IP44 standard waterproof, stable performance is guaranteed for outdoor use, no worry for all weather conditions. LED FlashBlue LED Flash at the button and receiver is a visual cue for host and visitor, it's also a fun and thoughtful design for the hearing impaired, as it lights up when in use. > Easy Installation2 steps Connect the portable receiver to any mains, and stick the transmitter on the wall with patch or screw provided. The receiver does not require a battery. Unplug the receiver so that the chime no longer sounds.