Crawlings Boy's Dump Truck Knee Pads 3" wide Body of knee pad is 80% premium cotton, 15% rayon, 5% spandex; soft, stretchable, and comfortable like a sock to move and grow with the child. One Size will fit most from a chubby 6th month old crawler to a 5 year old toddler scootering around town. One Size - 3 Center knee pad cushion is made of EVA cushion that is soft, flexible, and UV and water resistant. Low Profile EVA to cushion impact but not impede natural movement. Vented in the back for additional comfort. Perfect knee and elbow protection.