Breathable, flexible knee supportS 2.7cm =10.9 inch 15cm = 5.9 inch 13cm = 5.11 inch 30-35cm = 11.8-13.7inchM 27.5cm=10.9 inch 16cm = 6.2 inch 14cm = 5.5 inch 35-40cm = 13.7-15.7inchL 27.5cm=10.9inch 17cm = 6.6 inch 15cm- 5.9 inch 40-45cm = 15.7-17.7inchXL 27.5cm=10.9inch 18cm=7inch 16cm=6.2inch 40-50cm=15.7-19.6inchXXL 27.5cm=10.8inch 19cm=7.4inch 17cm=6.6inch 50-55cm=19.6-21.6cmXXXL 27.5cm=10.8inch 20cm=7.8inch 18cm=7.08inch 55-60cm=21.6-23.6inchS 45-60kg = 99.2-132.2lb M 60-70kg=132.2lb-154.3lb L 7