I purchased this, but the actual item was size M, so I couldn't use it. Below is the description from the person who purchased it. Please refer to it. It seems there are soft bones on both sides. The actual item is size M! I dislocated my knee and was going to an orthopedic clinic. I was recommended to buy this, but a second opinion said it wasn't necessary, so I'm selling it. Size: L, Made in Japan Original price: 14,000 yen I've only used it for about a week. Thank you.