Welcome to our store 138 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). 2Support Long Distance Connection: Working range up to 230 feet (70 meters) between receiver and transmitter, and infrared detection range up to 37 meters. 3Function: Can be alerted to visitors, notice door opening, scare off unwanted intruders, or even know when your children have accessed restricted areas. 4Easy Installation: The sensors can be installed or placed at any indoor position to provide you with a door entry alarm system. 5Widely 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 Alarm Material: ABS Application: Home, office, factory, shop security welcome and other places Battery: An infrared detector requires 3 x AAA batteries (without batteries) Voltage: 110 - 240V Infrared Detection Range: 3-7 meters Music: 38 music to choose, the side of the music button for adjustment Volume: three levels of volume adjustment (high, medium and low) side volume button for adjustment You can set voiced and silent (voiced: sound+indicator silent: indicator) Operating Frequency: 433MHZ Working Distance: 70 meters Package List 1 x Doorbell 2 x Infrared Detectors 4 x Bracket Accessories 4 x Screw 4 x Expansion Tube 1 x Instructions 100% Satisfaction - Our customers are our top priority. If you find any product problems after receiving the goods, such as damage and incorrect quantity of goods, please contact the seller immediately. We try our best to provide you with satisfactoryaftersalesservic