A:AnswerThe HyperDrive 7-port will not work on the Surface Pro 6. We do offer the 5-port, made specifically for the Surface Pro (original version through Surface Pro 6). The HyperDrive 7-port would work with the latest Surface Pro 7 that utilizes USB-C.
A:AnswerIt looks like a plastic/rubber audio jack to plug into certain computers that have one next to other thunderbolt port. I am guessing it is for added stability of the hub.