The back cover of the watch cannot be opened casually. Because the installation of the watch is carried out in a professional workshop, and the workshop has strict requirements on temperature, relative humidity, and cleanliness. The general environment cannot meet the corresponding requirements. This is only one aspect of the problem, another aspect is the sealing performance of the watch. As long as the watch is opened and then closed, the waterproof test must be done, and the sealing performance of the watch must be guaranteed to meet the technical requirements. The average person cannot meet this requirement. Considering the waterproof performance of the watch and the cleanliness of the movement, the back cover of the watch cannot be opened casually.