The outer shell of the helmet is made of super-light PVC plastic, which can withstand impact well. The lining material of the helmet is high-quality EPS foam, which can absorb the impact force well. Keep the weight to an absolute minimum without sacrificing safety for kid's cozy wearing.S size is suitable for Protective gear set for boys and girls aged 3-6. M size is suitable for boys and girls aged 7-11. Helmet size50 cm-54 cm. The helmet has an adjustable rotation knob and to make it fit flexibly and perfectly. Multiple adjustable elastic straps and Velcro closures fit for various knee Wrist Elbow circumference. This will reduce the safety hazard caused by falls.Knee Elbow Pads Wrist Guards Made of tough and durable materials .They are designed for kids sports safety protection especially. The breathable fabric lining design is comfortable and easy to clean. bring your child all-round protection.Our kids' bicycle Protective Gear Set can fully protect the safety of children, protect many Outdoor Activities, such as bike riding cycling, roller skating, skateboard accessories, scooter and more.it's the best gift for children on birthday, Thanksgiving and Christmas etc.7 in 1 Kids Helmet Set Provided with 1 helmet, 2 knee pads, 2 elbow pads, and 2 wrist pads.