Raise the antenna height above interference for greater rangeLight-duty fiberglass extensions raise antennas above potential interference from backstays or pulpits. Mounts between your antenna base and your VHF antenna or loran coupler. 1" male and female threads on ends. We recommend the use of an upper support bracket when used with VHF antennas or on fast powerboats. The 1' mast is commonly used with TV antennas.