If you can find a way to attach it so people can't steal it, the Miccus is the best I have used- it has great range, the sound is good (I haven't compared it to a better file format, but I haven't found anything objectionable in the sound), it has analog 3.5mm and optical in/out, detachable antennae, the company was very responsive when I called and best- it's not expensive. I paid $50 for the first one and a bit less for the second, both from Amazon. Easy to pair, uses Bt 5.0 and if needed, it can announce that it has successfully paired to a device- that announcement can be turned off. In addition, it can send or receive, which increases the range which, as I found, is excellent. Before I needed one of these, I 'knew' BT sucked, as most of us did. Less than half hour before bought the first one, I looked into the options after seeing BT work over a much greater distance, so I decided to give this a shot. It was here in less than 8 hours and when I set it up, I walked away and counted my steps- it never stopped streaming by the time I gave up and when I walked back to my garage, I counted 60 steps at just over 3'/step. The one I installed has three concrete block walls between it and the gym where the streaming devices are used.

[Link: miccus.com]