Unsure what the usb interface is for though as it doesnt seem to register as a device. Assembly was easy, even alone, but be sure to have your own set of tools because the wrenches they include are garbage, which is to be expected. Not really an "upgrade", but a side-grade. No worries about blisters or feet slipping out or fabric ripping ? very durable! Otherwise, theyre quite comfortable and look good. I know lots of people will bash me with comments, dont care ! I thought since they were to be used on a boat that they would be more durable than the ? magic eraser? I?ll stick with Mr Clean Regardless they work for just walking around the house and he says they are comfortable. But these slippers are wonderful. You can turn on/off both earpieces individually so make sure you have turned both on to get the sound in both - you can also used just one ear piece if you would like.