The infrared doorbell has an effective sensing distance of 4 meters and will play a pre-recorded sound when someone enters the detection range. Audio files can be customized by connecting the device to a computer via USB cable and copying new MP3 format audio files to the player. MP3 files will play automatically when the PIR sensor is activated. Note: The device is compatible with Win7/XP computers but may not be recognized on Win8/10 systems.Ideal for retail environments, the doorbell emits a warm welcome, greeting, warning, or voice message when human movement is detected. Different audio files can be loaded based on application needs to achieve the desired effect.Dual power options: powered by 3 AAA batteries (not included) or via the included Mini USB charging port. Note: Audio replacement is not supported through the Mini USB port.Security feature: When leaving the store, switch to alarm mode. The device will detect approaching individuals and trigger an alert to deter potential intruders.Memory function: The device retains selected audio and volume settings even after entering sleep mode or power cycling.Specifications: Model: Microsound V22.12 Product Type: MP3 Infrared Doorbell Audio Format: MP3 (Bit Rate: 8320 Kbps), high-quality sound with two volume levels: low or maximum Built-in Speaker: 8 ohm 1W speaker Sensor: Infrared induction with automatic detection Power Supply: DC 3V5V stabilized voltage Working Current: 100 A (Sleep Standby Mode); 130 mA (DC 4.7V) (Playback Mode) Infrared Detection Distance: 4 meters (45 angle) Sample Rate: 14 KHz Memory: Built-in 4 Mbit SPI FLASH memory Installation: Ceiling or wall mount Power Source: External USB power supply (DC 5V) or 3 AAA batteries (not included) Working Current: 100 A (Sleep Mode); 60 mA (Playback Mode) Humidity Range: 1085% RH Color: White Material: ABS Dimensions: 90 x 60 x 26.6 mm Package Contents: 1 x Audio Doorbell Note: Other items not included. Note: Lighting and display differences may cause slight color variations between the image and actual item. Measurement tolerance: 13 cm.