The nano ring hair extension is one of the newest types of semi-permanent extensions. It looks like a micro ring hair extension but is 90% smaller and almost impossible to see. In fact, even if you are wearing your hair up in a bun or a ponytail, the tiny rings will still be undetectable. Because the rings are lighter than the normal ones, they are more comfortable to wear. For these reasons, the nano ring hair extension is considered by many as the best type in the market.