I believe it is a Connexx Smart Transmitter 2.4, and potentially Costco item #1230845. I think the Rexton HA’s use the same one.
I have the Connexx Smart Transmitter and I like it a lot. For me it is not in the program list either on my phone or by the short button pushes. I only have 2 programs, Automatic and Noise/Party. I use Automatic only. To activate the Smart Transmitter I hold either of the program buttons down for about 2 seconds or use the Smart Direct app. Your hearing aids need to be programmed and paired to the Smart Transmitter. In the Smart Direct app there is in the top right of the white area a little TV icon. I tap on that icon and it activates the connection to the Smart Transmitter. Once activated the icon has a highlighted circle around it and adds an additional screen to the Smart Direct app. Swipe right or left to change Screens. Each Screen is labelled in the upper left of the white area, Volume or Smart Transmitter 2.4 V… . Volume screen controls normal hearing aid volume and Smart Transmitter 2.4 V… controls the TV volume in your hearing aids. This is totally independent of the actual TV volume in the room for everyone else. If I remember correctly you can have up to 8 pairs of hearing aids connected to the Smart Transmitter at one time each user controlled individually.
First screen shot is before I activate the Smart Transmitter. My crude little arrow points to the TV icon.
Second screen shot is wit the Smart Transmitter activated. There is the highlighted circle around the TV icon and there are 2 little dots at the bottom of the white area indicating that there are 2 screens and which one is active.
In summary I would recommend the Smart Transmitter, but it does consume your batteries faster. I get about 4 days with new batteries.
I traded mine in for a calculator. Then I stomped on the calculator.