Description: Built-in dual-speaker design gives it a clear sound. Side music and volume buttons allow you to adjust as needed. High frequency and infrared sensor design make it easier to use. The strong anti-interference power makes it possible to detect the movement of the human body normally even in dim and unlit conditions. Made of high quality fireproof ABS material, it is eco-friendly. The length of the receiver is 8cm, the width is 7.6cm, and the thickness is 3.3cm. The length of the transmitter is 8cm, the width is 5.9cm, and the thickness is 4.5cm. It should be installed at a height of about 2 meters. Wireless doorbell is suitable for home, office, factory, store, security welcome and other places. Item Name: Wireless Doorbell Material: Fireproof ABS Color: White Frequency: 433MHz Ringtones: 38 Chimes Transmitter Voltage: 4.5V Receiver Power Supply: Plug In Adjustable Volume: High, Medium, Low Receiver Socket Type: US Plug, EU Plug Transmitter Induction Distance: 3-7 Meters Transmitter Working Distance: Up To 70 Meters Sound Type: Voice and Indicator Light; No Sound Type: Indicator Light Transmitter Power Supply: USB Charging/3 x AAA Batteries (Not Included) Features: High Sensitivity, Low Power Consumption, Strong Penetrating Size Details: Receiver Size: 8cm x 7.6cm x 3.3cm/3.15" x 2.99" x 1.3" (Approx.) Transmitter Size: 8cm x 5.9cm x 4.5cm/3.15" x 2.32" x 1.77" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Operating Instructions: 1. The receiver plugged into the socket to power on, open the detector battery cover to load the battery. 2. The rotating bracket set into the back of the detector stuck. 3. The detector switch pushed to the ON position, wait 10 seconds after the self-test time can enter the normal working state. Package Includes: 1 x Receiver 1 x Transmitter 1 x User Manual