This cable is a physical foam coaxial cable that is mainly used for radio communication, broadcasting, network, etc. Its impedance is 50ohm. The Ingress Protection Code is IP55. And it is compatible with all our amplifiers that work at GSM, 4G/ 3G / 5G or several frequency bands. . It's recommended to use long cables only with advanced powerful boosters, not with the basic ones for better efficiency. 20m is also mostly used for outdoor application.