I saw a brief remark that the Miccus Transmitter had minimum latency and ordered one. It worked but suffered infant mortality and I returned it. I noticed that the Indigo BTRT1 was the same unit but $10 cheaper and reordered it instead. When it came it was identical down to the packaging.
Both units were easy to pair with my Resound Phone Clip +.
This is a low latency BT 4.1 device. Low does not mean no. For general viewing it might be considered no as watching a regular show is a pleasant experience. Where it is mildly noticeable is in a closeup.
An example was a closeup of our local weather reporter with a full face shot. It was great at the start of a statement but very slightly deteriorated as the speech continued. After a pause, it again went from little or no to slight. Probably the 40ms in the spec. Still, I didn't find the minor latency annoying. Under normal viewing conditions, it isn't apparent.
I have to give the $34.95 Indigo good marks. I used a Toslink splitter to allow it and my sound bar to share the TV's optical output.
If you have occasional trouble with TV speech, you should find this can improve thing. I find it somewhat better than my sound bar in stereo with a feature called "Clear Speech" enabled. On the Indigo, background sound are slightly more muted going though the Phone Clip Plus which improves understanding. Those with accents are clearer than using the sound bar.
The phone clip and the app will adjust volume. I can get around 3 hours of streaming on a charge. It start to break slightly at that point and I plug it in while still playing and place it on the end table beside me where the clip returns to uninterrupted streaming.