Aluminum alloy shell made by micro-arc oxidation process makes the shell surface harder and stronger. Strict quality inspection standards and fine cosmetics. Since the USB 3.1 standard needs to be backward compatible with USB2.0, every time this USB Type-C female to female adapter is connected there may be a 50% chance that it will be non-functional. Just unplug and reverse it and re-insert. This is an common standard issue with some older type C devices. With that said it widely functions with most Type C devices. For example for MacBook Pro, Surface Book 2, Samsung phones such as Galaxy S23 to S10, Note20, 10, LG G7 V20, Google Pixel, Chromebook, and more.