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.