I've just given up doing ERS training, having spent several years also examining blood biker's for suitability in the past. Most people are now on bluetooth, and have been for some time. I've got a full Intaride set with plug-in power unit to save carrying spare batteries.
It's also got FM radio and power button to boost the range.
Not really sure what it's worth but I suppose I'll sell it now.
Also got camera, which I occasionally used for feedback/debrief, expect I'll shift that on too.
How times change, and quickly too.