When buying a new helmet, if you can't tell if it is safe or not by looking at the helmet, then purchase it at your local bike shop. If you are not sure if the bike shop can provide information about the safety of the helmet, then purchase the helmet online. That way, you get the information about the safety of the helmet without having to worry about the helmet being damaged.
First, make sure that the helmet you are buying is compatible with your bike. If you are buying a helmet because of safety, make sure that it is certified to be safe for biking. Second, make sure that the helmet is comfortable. You don't want to spend all of your time on the bike uncomfortable. Lastly, make sure that the straps are comfortable and that the helmet fits your head properly.
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