Inside each recorder there is a flash memory - like a memory stick. On the end there is a USB connector so that you simply plug into a computer. No software needed. The recordings are in MP3 format and can be saved and played in any media player.
The microphones themselves have a red button for record and a green for play back. The speaker on the play back is limited. I would recommend that you play them back through a computer - this will also mean that you can see all the recordings made in a session & save / clear the memory at the end of a recording session.
These photos show KS1 and Reception children using easi-speak. I found that it was worth spending some time talking to the children about interviewing technique, holding the microphone when asking or answering questions etc.
Click on the TTS logo to see Easi Speak website.