Features: 1. Power switch/record switch 2. Volume plus/next track key 3. Volume minus/MP3 music conversion key 4. 3.5mm jack 5. Work indicator lamp 6. Up to 48 hours of continuous recording on 4GB model 7. Recorded files in WMA/MP3 format 8. High capacity 9. Built-in rechargeable lithium battery 10. USB storage write protection 11. One-touch recording and high-quality recording 12. Recording via high-grade built-in microphone 13. Phone conversation recording 14. Functions as a driver-free USB flash drive 15. MP3 playback function Specifications: Battery life: approximately 3-5 hours during continuous recording Playback time: approximately 3-5 hours Recording format: WAV Music formats: MP3, WMA, WAV Sampling frequency: 48kHz Bit rate: 192kbps Dimensions: 47 x 19 x 7mm Notes: Due to high recording quality and advanced parameters, recorded files may be large in size. Please transfer and save files promptly. Warning: This device features an intelligent reset system. Always save recorded files before connecting to a computer. Package includes: 1 x 8/16/32GB voice recorder 1 x user manual