A tp-link UB500 is a small USB bluetooth device, the kind of thing you would buy to connect a bluetooth mouse or headset to a computer that does not have built-in bluetooth.
This appears to apply to UB400 devices as well.
Here is a tp-link page where they say that it is not possible to use two of the same UB devices in the same place, but a UB400 and a UB500 will work.
https://www.tp-link.com/latam/support/faq/2744/