Have you tried the Phonak PartnerMic ? I understand that it’s not comparable to Roger On, but it’s the “basic” device for this functionality and is much less expensive. I have one and find it useful, although relatively limited.
I had not then, but with this encouragement I borrowed one and tried it. Thank you @greg.smith for the info! The Phonak Partner mic is one of two technologies I have now acquired.
I contribute commentary now based on my own try-outs: Roger On has definitively nicer sound quality, and has better controls in the My Phonak app. However, in addition to its much higher cost, it has more lag time in turning on or off, and has some irritating quirks like coming unpaused or changing mode when I did not intend that.
The Phonak Partner mic is smaller, lighter, cheaper, faster (in terms of time to manage its use) and simpler to use. I am very tech savvy but when I am trying to focus on other things I am delighted with this little fob that simply works without any muss or fuss. It requires no “receivers” a.k.a. Roger licenses which contributes to its ease and affordability. You turn it on, push a pairing button if that was not the last similar device you paired to, and about 5 seconds later you are good to go. If it was the last device you paired to, you merely turn on the switch and it is working in about two seconds. When you want to stop prioritizing sound from the partner mic, slide the switch off and it disconnects in less than a second. The mechanical switch has color inside so I don’t waste time figuring out if it is on or off.
I bought one for about $60 including shipping on Ebay that was listed as working from a dealer with good satisfaction scores. It works perfectly.
I also decided to gamble on a lot of 6 Phonak Partner Mics for $40 including shipping being sold “for parts” from a dealer not specializing in hearing aid tech as the description of what was wrong sounded suspiciously like the operational quirks to the LED programming that I had noticed on the new fully functional Partner Mic my audiologist had loaned me to test out. I enjoy fixing small things like mechanical watches so I also thought it might be entertaining to try to diagnose and combine parts and see what I could get to work. Of the 6, 3 simply work after fully charging, 2 work but have batteries that drain too quickly on standby, and one does not work. So that was 3 fully functional partner mics for $13.33 each. Score! One to keep at work, one to keep at home, one to keep in my purse…

The sound from the Partner Mic is not as clear as the sound from the Roger on, and it only covers one of the Roger On’s several functions, (that of hearing a partner without having to stand right in front of them) but I am quite satisfied. I will also point out for anyone who cares that the partner mic has a shorter distance range as verified by me, less ability for the signal to penetrate through walls and turned backs, and is flightier in having more brief silences when its programing kicks in to protect from wind noise or sound spikes. My audiologist tweaked my “Partner Mic” program in my hearing aids in a way I don’t have access to myself, and hopefully that will cut down on the brief sound cut-outs.
All in all, I am delighted with my affordable handful of helpful little tech devices. It is totally worth the $13.33-$60 I paid for each of my Partner Mics. I can converse in the car, carry on a real conversation with someone at the table while I rush around doing stuff in the kitchen, and the next time I have to go on a torturous tour in a group I am totally prepared for the revolutionary concept of hearing the tour guide.
P.S. Updating my commentary monologue in case anyone cares…Alas, after further experimentation and trial under real world conditions, most of the ultra cheap “non functioning sold for parts” partner mics that at first seemed to work really did not work in a useful way–at least not yet. They turn on, pair, and broadcast great! But they won’t stay switched off again…which causes its own hilarious and/or irritating problems…I totally get why they would be returned as defective and sold for parts! I have been having fun playing with the parts, and am not upset about my $40 gamble which has therefor brought 1 functioning mic and several hours of technofigit entertainment.
P.P.S. the $60 ebay Partner Mic sold as functioning continues to function usefully and helpfully. That would be my recommendation for anyone who just wants things to work.