Dust covers are only used when optical fibers are not used. A fully equipped optical fiber generally has small dust caps at both ends, so don't throw it away casually. The surface of optical fiber plug is thinner than the mirror, and fine dust and even fingerprints are big obstacles to optical signals, which may affect the quality of optical signals. So pay attention to keep these two dust caps, and remember to cover them in time if the optical fiber is not needed one day to prevent the optical fiber from being used normally next time. If your light cat is configured by telecom, you can contact 10000 to handle the use problem.