Using your CORE Action Sports Helmet is easy. First, measure your head size following the size guide to pick the right fit. Then, put the helmet on your head and adjust the chin straps so it sits snugly but comfortably. Make sure the helmet covers your forehead about 1 inch above your eyes. When riding, always fasten the red safety buckle on the chin straps. As for maintenance, you can remove the 3 - piece inner padding and wash it regularly to keep it fresh. Keep the helmet in a cool, dry place when not in use. Avoid exposing it to extreme heat or sharp objects that could damage the EPS foam lining or the ABS outer shell. Check the helmet periodically for any signs of wear and tear, and if it's been in a significant impact, replace it for your safety.