Brand new, unused item. I purchased this item from a Mercari seller who is an authorized Surf8 dealer, but the size didn't fit, so I'm listing it immediately. This is a Surf8 5mm round sock. It's a size M, but it runs small, so it's recommended for those with foot sizes of 23.0-24.5cm. It was very difficult and time-consuming to put on when I tried it with my 25cm feet.