One of the wonderful things about wearables is how many different sizes, shapes, and styles they come in. And each of them usually uses its existence on a different part of the body to accomplish different things, be it giving you alerts, tracking your health, or monitoring the world around you. A lot of wearables have even gotten good enough now that you can't tell that they're a wearable — or, at the very least, that you don't have any idea what they're doing. If you think you can tell what a wearable does just by seeing it on someone, take the quiz below to find out how well you'd really do. But one word of warning: just because a wearable claims to do something doesn't mean it'll actually excel at doing it.