This NMO to 3/8"x24 adapter permits 3/8"x24 type antenna to attach to an NMO mount and realize the adaptation between different interface devices. Swap Antennas with Ease: This NMO to CB Antenna Adapter allows you to swap NMO antennas without changing/ adding another mount, just simply insert the antenna and tighten it firmly, and will not break your whip antenna easily.