The original "nano" version.It's black, and it's about 0.5cm proud of the USB connector.
That should work, the link describes it as compatible with Raspberry Pi / Pi2. Old skool!
Mine is not the nano version, and I see now it is actually an entirely different model # too, EW-7722UTn.
At 300mbps it has double the bandwidth of that generic one I have, and they describe that extender cable as having a hardwire in it, which is why it doesn't droop at all under the weight of the adapter:
I found my Amazon purchase, August 2016, and they still list/sell that exact package.