Whether selling helmets is illegal depends on whether the seller has a business license. If he had a business license, he wouldn't break the law. Those who are not suspected of the crime of illegal business operations are generally sentenced to fixed-term imprisonment of not more than five years or criminal detention, and a fine of not less than one time but not more than five times the illegal income. Article 225 of the criminal law? The crime of illegal business operation violates the provisions of the state and commits one of the following illegal business operations, disrupting the market order, and if the circumstances are serious, it shall be sentenced to fixed-term imprisonment of not more than five years or criminal detention, and shall be fined not less than one time but not more than five times the illegal income; If the circumstances are especially serious, he shall be sentenced to fixed-term imprisonment of not less than five years, and shall also be fined not less than one time but not more than five times his illegal income or his property shall be confiscated: (1) dealing in franchise, monopoly goods or other commodities whose business is restricted by laws and administrative regulations without permission; (2) buying and selling import and export licenses, import and export certificates of origin and other business licenses or approval documents stipulated by laws and administrative regulations; (three) without the approval of the relevant competent departments of the state, illegally engaged in securities, futures, insurance business, or illegally engaged in fund payment and settlement business; (four) other illegal business activities that seriously disrupt the market order.