Combo split bead kit for dual band antenna like 2 meters/450 MHz (J-poles, dual band verticals, etc) - 4 beads covers VHF and UHF band. Each set provides over 500 ohms of common mode resistance to keep antenna current off the coax and on the antenna for better radiation pattern and less coax radiation which can cause RFI to nearby electronics.
Simple to install at antenna feed point - just snap on!
Simple, effective and cheap solution - buy it now!
12:1 Ununs are useful between coax and long wires with a load impedance near 600 ohms like a beverage antenna. Shortwave listener antennas also can benefit with the 12:1 unun and it may provide a better match than 9:1 ununs – this means quieter noise levels and stronger signals so you can hear distance stations easier.