The waterproof and dustproof rating of the watch is certified by SGS. This company is currently the world's largest and most qualified product quality control and technical appraisal company. The temperature difference before and after a bath will cause thermal expansion and contraction on the rubber ring of the watch. In the long run, the rubber ring may have a gap and thereby alter the waterproof rating of the watch. Additionally, bathing products will accelerate the aging of the watch's rubber ring and shorten the watch's service life. Water vapor also diffuses everywhere in the bathroom. Additionally, the watch shouldn't be in contact with soap, bath lotion and organic solvents. When these liquid substances are allowed to adhere to the watch for a long time, abnormalities such as discoloration may occur.