This is a protector set for infants. Although it depends on the size of your child, it's suitable for children up to around 3 years old. I purchased this separately when I bought a Strider, but I only used it once at the beginning, so it's almost new. It's a three-piece set for knees, elbows, and palms. It comes with a mesh bag, which is convenient. It's easy to attach with Velcro. Please feel free to comment if you have any questions.