To use this helmet, first adjust the fit system so that the helmet fits snugly on your child's head, with the size between 50 - 54 cm. Then fasten the adjustable straps under the chin. Make sure the helmet covers the top and sides of the head properly. When your child is riding, this helmet will keep them safe. Remember, always check the helmet for any damage before each use. If there are cracks or the fit system is not working well, replace it immediately. To maintain it, clean the exterior with a soft cloth and mild soap. Don't use harsh chemicals as they may damage the ABS shell. Store the helmet in a cool, dry place when not in use.