KJB Security D4100 SleuthGear Digital Voice Recorder 2GB Internal Memory record up to 130 hours of Audio with  Built in Speaker MP3 & WMA File Playback Long Battery Life Windows Compatible Recording up to 130 hours (2GB) Mobile phone Recording VOR (Voice Operated Recording) Built in Speaker Erased Recording files New Stereo High Quality recording 4 Multi Recording Mode (HQ/SP/LP/STEREO HQ) Listen & Repeat Support Recording Appendix into one file Power Supply by USB port Extra Power Supply by external AAA battery pack MP3 & WMA File Playback Voice Timer Recording Setting Battery life approximately 15 hours max Compatibility: Windows 98SE, 2000, Win XP, Windows Vista (Not Mac compatible)