There are several brands of USB 3.0 to Gigabit Eithernet adapters out there as well, and they are a bit cheaper than the Apple model, if that matters. They all use the same chipset (ASIX AX88179), and require a driver to be installed, whereas the Apple Thunderbolt device requires no driver. I have a couple of the Plugable ones, and they work equally as well as the Apple product (same transfer speeds). I have the Apple model as well, as there are times it comes in handy. My preference is to use the USB model.
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