The 1" Shakespeare Base Mount is a military style mounting kit for quick disconnect of antennas with a 2.5" mast. this is usually Hi-Q-6 Antennas, however, there are some Hi-Q antennas that have a 2.5" mast. This kit requires some modification to the mast base holes of older antennas and requires a 1/2" x 20 TPI Mounting Bolt.