Professional Customer Service: We always provide customers 24-month warranty and online after-sale service. Please contact us for replacing the correct size if it's not suitable. NOTE: carefully check the size chart from the left picture, M: 13.8"-16.5", L: 16.5"-18.5", XL: 18.5"-21.7". Enjoy Your Activities: KGONE Knee support is the perfect fit for any activity that involves a great amount of stress on the joints like Baseball, Basketball, CrossFit, Soccer Golf, gym, Hiking, Running, Tennis, Volleyball and more! You'll be able to enjoy exceptional Knee support while still maintaining your peak performance and a full range of leg motion. Comfortable to Wear: Using 3D circular technology ensures a way longer life. Our knee brace provide a comfortable, snug, without cutting off your circulation or restricting your motion. The compression knee support fit for both men & women, kids and adults. Non-Slip Knee Support: In the market, most of compression knee support are very easy to slip down, in order to solve this issue, we add 2 waves silicone at the top cuff to increase friction, so that the knee brace won't slip down. IMPORTANT! DON'T GUESS YOUR SIZE: Please Consult our Size Chart (IMAGE 2) and follow the Measurement Instruction before you place an order (The knee support's size you need is nothing to do with the size of your clothing or competitor's size). It takes less than a minute to measure. Please see image 2 for sizing diagram.