Sold as a set of two. These are thick and sturdy, providing firm support for your knees. Ideal for those with O-legs, X-legs, or those experiencing inner or outer knee pain, and for those who want to restrict knee rotation. Purchased in November 2023, one was used only once and is practically new. The other has been used several times, and the belt portion is slightly deformed. Size M is for those with a thigh circumference (10 cm above the center of the kneecap) of 41-46 cm. I am 40 cm and it was a little big, but it held firmly and relieved my knee pain. How to use: For those with inner knee pain → wrap inwards For those with outer knee pain → wrap outwards Please refer to the website, etc., for more details.