Feature:1. 38 Melodies And Adjustable Volume:The receiver has 38 ringtones for your choice. 3 adjustable volume levels, you can set voiced and silent (voiced: sound+indicator silent: indicator).2. Support Long Distance Connection: Working range up to 230 feet (70 meters) between receiver and transmitter, and infrared detection range up to 37 meters.3. Function: Can be alerted to visitors, notice door opening, scare off unwanted intruders, or even know when your children have accessed restricted areas.4. Easy Installation: The sensors can be installed or placed at any indoor position to provide you with a door entry alarm system.5. Widely Use: Great for homes, offices, garages, yard, and shopping malls. Also can be used at the front door, back door, garage and driveway.Specification:Item Type: Motion Sensor AlarmMaterial: ABSApplication: Home, office, factory, shop security welcome and other placesBattery: An infrared detector requires 3 x AAA batteries (without batteries)Voltage: 110 - 240VInfrared Detection Range: 3-7 metersMusic: 38 music to choose, the side of the music button for adjustmentVolume: three levels of volume adjustment (high, medium and low) side volume button for adjustmentYou can set voiced and silent (voiced: sound+indicator silent: indicator)Operating Frequency: 433MHZWorking Distance: 70 meters.Package List:1 x Doorbell2 x Infrared Detectors4 x Bracket Accessories4 x Screw4 x Expansion Tube1 x Instructions