The infrared doorbell has an effective sensing distance of 4 meters and will play a preloaded 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. The MP3 files will play automatically when the PIR sensor is activated. Note: The device may be recognized on Windows 7/XP but not on Windows 8/10. Ideal for retail environments, this doorbell emits a warm welcome, greeting prompt, warning alert, or voice message when human motion is detected. Different audio files can be loaded based on specific application needs to achieve desired effects. Power options include 3 AAA batteries (not included) or connection via the included Mini USB port for external power. Note: Audio replacement is not supported through the Mini USB power connection. Features a practical anti-theft function. When leaving the store, switch to alarm mode to detect and alert approaching individuals, helping to deter potential intruders. Designed with memory functionality. Once audio selection and volume level are set, the device retains these settings even after entering sleep mode or power cycling. Specifications: Model: Microsound V22.12 Product Type: MP3 Infrared Doorbell Audio Format: MP3 (Bit Rate: 8–320Kbps), high sound quality, two volume levels: low or maximum Built-in Speaker: 8 ohm 1W speaker Sensor: Infrared induction, supports automatic detection Power Supply: DC 3V–5V stabilized voltage Working Current: 100uA (Sleep Standby Mode); 130mA (DC 4.7V) (Playing Mode) Infrared Detection Distance: 4 meters (45° angle) Sample Rate: 14KHz Memory: Built-in 4Mbit SPI FLASH memory Installation: Ceiling or wall mount Power Source: External USB power supply DC 5V or 3 AAA batteries (not included) Working Current: 100uA (Sleep); 60mA (Playback) Humidity Range: 10–85% RH Color: White Material: ABS Dimensions: 90 x 60 x 26.6mm Package Includes: 1 x Audio Doorbell Note: Light and display differences may cause slight color variation between the image and actual item. Measurement tolerance: ±1–3cm.