4GB built-in memory; Expandable microSD(TM) Card slot; 4 selectable recording modes; Voice-activated recording; 4 separate internal message folders with 1 message folder for microSD(TM) Card; Stores up to 99 messages per folder; Built-in speaker & microphone; High/low microphone sensitivity settings; External microphone & earphone outputs; Multifunction LCD display; Button lock switch; USB connectivity; PC & Mac(R) compatible; Requires 2 AAA batteries; Includes USB cable;