Spiral Elastic Knee S-XL (3623) This knee sleeve is made of knitted beige elastic. It is tapered in the back for better fit. It has an open patella and medial/lateral spiral stays for added stability. Sizing: SizeKnee Circumference XS 10.5″ – 11.5″ S 11.5″ – 13″ M 13″ – 14.75″ L 14.75″ – 16.5″ XL 16.5″ – 17.25″