M stands for clothes size.

what must be on the Chinese trademark? That is, Register stands for registered trademark.

in foreign countries or English-speaking countries, there are TM trademarks. Represents a registered trademark.

or when you buy some products that you don't know or are not well-known, you must first check whether they are registered trademarks, and don't confuse the fake with the real, which will infringe on your personal interests.