The Aerpro CBBL2 Antenna Base and Lead is compatible with 477MHz UHF and 27MHz AM CB Radios. It is fitted with 5 metre RG58 coaxial cable which is pre-terminated with an FME connector making it easy to install through the firewall grommet in vehicles. An FME to UHF PL259 screw on adaptor is also included for hassle-free installation. Simply add a 477MHz UHF or 27MHz AM antenna whip with a 5/16" thread for reliable CB communications.