This is a set of four knee pads for use in youth baseball practice uniforms, etc. 2mm urethane foam is inserted within the same 4-layer smooth fabric as the uniform. Even if one side tears, it can still be used on the other side. Your enthusiastic child, whose practice pants get holes quickly, can use these for a long time! Off-season!! How about maintaining your child's pants? This product requires the customer to sew it on. (See photo 5 ※ Pants are not included) Size (See photo 2) Length: Approximately 19cm Width: Approximately 11.5cm As this is a handmade product, there may be some size errors, distortions, and fraying. Also, purple lines may remain, but they will disappear after a few days. Please purchase only if you understand the above.