Long Range SignalPenetrating 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 Ringtones in CD quality are your choice by pressing the receiver button, with 4 adjustable volume levels 25dB-85dB. Waterproof DoorbellThe transmitter button made of superior material is waterproof to IP44 standard, stable performance is guaranteed for outdoor use, no worry for all weather conditions. Easy Installation2 steps Plug the portable receiver into any mains, and stick the transmitter on the wall with supplied patch or screw. The receiver does not require a battery. Unplug the receiver to stop the chime ringing. LED FlashBlue LED Flash on the button and receiver is a visual cue for host and visitor, it is also a fun and thoughtful design for the hearing impaired , as it lights up when in use.