When filing for an external hard drive (Time Machine) really handy and quality. The shelf can be mounted on very well at the Stand of iMacs. Here were located in one of the screw fasteners even metal shavings from the precision mechanical milling, so that I could not assemble correctly determined the shelf for a long time, till I can find with a magnifying glass, the metal shavings. In the usual for Apple products very elaborate presentation of the product and the very high price rather weak.