Distinguish front and rear doors - You can program each button to a different tone so you know where your guests are. This is a very convenient feature for multiple doorway entries. Longer Range - Up to 1000 Feet (300m) in the open air from the transmitter (150m if there are walls). Either you are occupied in the bedroom or at the kitchen, our wireless doorbell kit can remind you that someone is calling from outside. Never worry about missing visitors. 60 Melodies & 5 Levels Volume & LED Flash- The wireless doorbell offers a wide selection of 60 tunes for your choice. 5-level of volume range from 0dB to 110dB, silent mode with just LED flash is available when you don't want to be disturbed. IP44 waterproof - The doorbell push button is rated IP44 and weatherproof for outdoor use,the doorbell chime is suitable for any home, townhouse, apartment, office, school, hospital, hotel or other application. Our wireless doorbell is certified with CE, RoHs, FCC. Expandable and Easy Installation - Expand your existing doorbell system with up to 8 transmitters and unlimited receivers. Simply plug the main doorbell chime into a wall outlet, install the push button with provided double sided tape or screws.