Reddit mentions of Olympus DP-201 Digital Voice Recorder

Rape accusation - it's a good start that OP is 1500 miles away. That is a relatively airtight defense.

However accusations still remaining include harassment, etc. The gf's MO seems to be to try to threaten things a few times before making good on the threats, so I would pick up one of these, or an equivalent phone app, to record all calls. If you catch someone threatening to make a false allegation against you, that goes a long way.

Actually these days you can get flash memory based ones - though they maybe a bit smaller than an old cassette tape walkman. Tape may also be familiar to her.

Those devices would also record - so there may be a way to disable recording perhaps on that particular device.

I searched google for: amazon large buttons recorder flash

And got some links like these:

https://www.amazon.com/slp/digital-voice-recorder-with-large-buttons/avtmdx2au6sr6j2

https://www.amazon.com/Digital-Voice-Recorders-Audio-Video/b?ie=UTF8&node=227758

This one has large buttons:
https://www.amazon.com/Olympus-DP-201-Digital-Voice-Recorder/dp/B006ZW4IVE

Again these are mostly for recording, so have large record buttons.

Here's one that's just a player:

Sandisk 8GB Clip Jam MP3 Player (Black)

These are USB memory stick readers with larger speakers - as an example of this type of device:
https://www.amazon.co.uk/dp/B007NIKJM6

You mean something like this? It's about 25 bucks, and can record quite a bit.