X4 Air User Manual Attach External Devices You can remove the USB Port Cover to attach external devices. 1. Open the USB Port Cover and pull it off. 2. Once removed, you can install external mics, the X4 Air Quick Reader, and other accessories. 3. When you're finished, reattach the USB Port Cover by hooking it onto the metal bar and closing it. Make sure it is tightly closed to ensure waterproofing is not affected. 24