Digital voice recorder memory expansion secure digital sd max recording time 700 h recording formats dss dss pro mp3 pcm connections memory card slot usb 20 headphones microphone features built in speaker function pc connection recording function overwrite play function mp3 playback playback formats mp3 display tft display size 24 inch display size cm 61 cm operating time 23 h speaker diameter 28 mm output mw 200 mw dimensions 53 x