Does what it should, with good transfer rates. At the iMac in 2012, however, with the following unpleasant side effect: The connection to the Dock is briefly separated when only one plate removed mechanically or is doing so. This leads to unsightly disconnections, also move the copy /. Whether the problem is with the chipset of the Dock's or at the USB3 Implementation of Apple I can not say. I would have liked to the desired a slightly longer cable.
