The left and right springs support the knee and cushion the shock Multiple vent holes design, super breathable and comfortable Soft and high elastic band provide fixed compression for your knee Provide enough support for the knee, keeps the knee stable during exercise to avoid injury Magic tape fixing design, easy to put on and take off Specifications: Size: M/L/XL/2XL Main material: elastic band\mercerized cotton\magic tape, support strip M upper knee circumference: 33-41cm, lower knee circumference: 29-34cm L upper knee circumference: 37-45cm, lower knee circumference: 31-37cm XL upper knee circumference: 41-49cm, lower knee circumference: 34-40cm XXL upper knee circumference: 45-53cm, lower knee circumference: 36-45cm (Note: There are errors in manual measurement, please understand, all are subject to the actual product) Package included: 1 x Pair of Sports Knee Guard