They have different port types and configurations, and they vary in price as much as size and shape. Use a USB-C adapter (or “hub” or “dock”) to connect monitors, printers, MIDI instruments, hard drives, SD cards, modems, and other devices deemed too big for sleek, modern computers. USB-C adapters allow you to connect all (or most) of your peripherals to your computer via a single USB-C port. New laptops require new ways to connect old devices.