When you activate the PIR sensor, your MP3 files will automatically reset (Note: they can usually be identified on Win7/XP computers, but not on Win8/10 computers). You can load different audio files depending on the application to get suitable effects. Practical anti-theft function: When you leave the charging, the sound enters the ringing mode. The player can attract and remind those who want to catch and stop thieves. Two MM power supply range: equipped with AAA batteries and three-position USB ports, which can be powered by three AAA batteries (not included) or USB ports. (Note: Do not use USB instead of audio) The effective door of the infrared buzzer is 4m. When someone enters the effective detection range, the PRT sound will reset. Audio files can be replaced. Just connect them to your computer via USB CBLE and copy new audio files (MP3 format only). You can choose your own voice