This is an inferior copy of the FiiO UTWS1. That is to say, the housing is identical (except for the plastic button while FiiO has aluminium), but internal components are inferior and functionalities more limited. It's such a shameless copy that FiiO has a comparison on their website. Anyway, the FiiO is superior and about $45. Borderline fakes like this should be boycotted.
RazzcalI have the Fiio model. I am considering buying this model as the charging case uses USB-C and the Fiio requires you to plug in two micro USB cables, which is a total pain. I'm also having issues with one of the connectors on the Fiio being finicky. I disagree with your assertion that these are completely inferior.
BazirkerI've had the bt20s pro for 3 months now. Never had a sync problem or dropouts, the charging case is a dream. Working 10-12 hour shifts and being able to use head/ear phones(no wires) and not worry that they will die is the reason I got these. Worth every penny.
I'm using these with fiio fa1