5er Link Technology line of protective dust caps for popular styles of fiber optic connectors protect fiber connectors from contaminates and damage that can cause serious network slow downs or crashes. Whenever a fiber cable is not plugged in, it should always have a dust cap protecting each connector. By simply covering your fiber connector end faces, network uptime and performance can be greatly improved. Dust cap performs a significant job in optical fiber networks. These simple yet very effective little parts prevent the ingression of dust, dirt, oil, and other contaminants into the open ports. We all know that even a little contaminant can damage the polished end-faces of the fiber core