HUGGAH Dinosaur Bike Helmet for 1-3-5-8 Toddler Baby Kids, Lightweight Bicycle Helmet for Cycling Skateboard Roller Skate & Multi-Sports,2 Sizes for Boys and Girls

" The case is made of PC to prevent crushing after impact.The EPS foam material in the center serves as a cushioning protection.And the innermost layer is air cushion sponge material to increase the comfort of wearing. Find a measuring tool Measure the circumference of your head about 2 cm above your brow bone Choose the right size for your head based on the measurements Choosing a suitable model and size not only increases the comfort of wearing,but also makes the helmet more firmly worn an our head,in order to better protect our head. 18.9-20.5 inch (48-52cm) 19.7-21.3 inch (50-54cm) This dimension is the result of manual measurement, there is about 1cm error, please measure your original bike seat dimension before ordering. 0.66LB(300g) 0.66LB(300g) Bike / Blance Bike / Roller Skate / Scooter / Skateboard / Cycling 1 * helmet "