The mobile phone protective case is a product made of metal, plastic, silicone, etc. The mobile phone protective case basically has three functions: protection, decoration, and function. Mobile phone protective cases are no longer a purely practical commodity. With the popularity of mobile phones among young people, almost every young person who pursues fashion wants to have a unique mobile phone. Grooming their phones has gradually become a way for them to show their individuality. In response to this trend, phone case makers have introduced a number of products with better workmanship and more unique color patterns. This makes the types of mobile phone cases more diverse. When purchasing a color cover, first check whether the background color of the color cover is similar to the color of the surface. Simply put, the plastic material used for the white shell should preferably be white, and the plastic material used for the black shell should be black. If the base color is similar to the color of the surface, even if the surface coating of the color case is scraped off in the future, it will not become unsightly. The specific inspection method is to first turn over the color shell to see if its inner surface color is the same as the outer surface; secondly, check whether the color of the color shell is uniform; check again whether the printed pattern on the color shell is within the specified range, if the edges of the pattern are all If it extends to the inner surface of the color shell, it means that the craftsmanship of this color shell is not good enough, so it is best not to consider it; finally, be sure to remember to check the shell body for scratches and other problems.