Features: Only supports MP3 audio playback, two volume levels are optional. Human body induction, induction distance up to 4 meters. Built-in 8Ω1W speaker, built-in 32Mbit flash memory (4Mbytes). Two playback modes: full loop playback, single loop playback. Press the A button to play the previous sound and the B button to play the later sound. Download audio files from your computer via USB interface. Power mode: three AAA batteries or USB power adapter. Technical data: Material: ABS Colour white Power supply: USB/3 x AAA batteries (off) Audio: only supports MP3 Volume: two levels Detection distance: up to 4m Speaker: Built-in 8Ω 1W speaker Memory: built-in 32Mbit (4Mbytes) flash memory Memory expansion: does not support List of packages: 1 x Motion Sensor Doorbell 1 x Bracket 2 x Stickers