Designed to stay with your child as they grow, the pads will fit over elbows if they no longer fit over the knees.Featuring our patented VPD Air material for protection, the exceptionally lightweight and well-ventilated protector has a barely-there feel that ensures your child wont get too hot or uncomfortable while out riding trails. The material moves with easily with the body for ultimate freedom of movement.The protector is encased in a soft stretch fabric to ensure the pads are comfortable against the skin, and reinforced material on the outer wont tear even after years of repeated falls. Antislip neoprene patches help keep the protectors in place, and Velcro fastenings can be effortlessly operated by children, so its always easy to get the childrens body armor on and off.For knee use, measure circumference 10cm above the knee:S/14-20cmM/16-24cmL/20-34cmFor elbow use measure biceps circumference.