This audio player is called Microsound.The player will play automatically as soon as the PIR sensor is activated.The audio files can be replaced.Can be used as a doorbell, when the customer walks through the door, he can say "Hello, welcome".Use: Create an audible warning for a restricted area. Sound Security Alarm Create a special welcome at the front door. Get attention by adding speech, music or sound effects to a retail outlet.Features: MP3 audio format. Two optional volume levels, small or maximum. Human body detection, detection range up to 4m. Built-in flash memory of 32 MB (4 Mbits). Play Modes: Single Game, Sequential Game Audio files can be replaced. You can download audio files directly from the computer.Technical data: Power supply: 3 x AAA batteries or USB power supply, DC 3V-5V Working current: Standby mode = 100uA; Reading mode = 130mA Audio format: MP3, transfer rate: 8 - 320 Kbps. Audio output power: 8O/1W Infrared induction range: =4m (120°angle)How to update audio files? Convert recording to MP3 format. Connect the drive to the computer by USB cable. A removable disk will appear on the computer. Format the "removable disk". Open this removable disk and then copy the files to it.Notes: Before copying, delete all files from the manufacturer, and then copy your own files to this device.