I suspect it’s a twist to unlock and open style.
if you notice at the 12 o’clock position there is a molded circle on both the clear shield and the case it self.
I think you are meant to twist the clear shield counter clockwise till the half circle reaches the T.
first people reference but didn’t explain a point.
if you get a ”Spotify connect” device, they have enough brains that the stream goes straight to the device instead of your phone. This means your phone basically acts as a remote, but you can walk away with the phone or take a call and the stream doesn’t interrupt.
Other streaming services can work the same way bit I don’t know their trademark name.
if the streamer is relying on “dlna” to move the signal around, this benefit doesn’t apply.
as for my personally recommendation, look at the phorus pr5. Spotify connect, Good DAC, cheap, reliable, etc. you can always step up from there.