This is a flag mount that will mount on any 2.5 inch round tube on the tower. The mounts are universal and can be mounted on the port or starboard side.
The flag holder is just over 1 inch so it will accept a 1 inch flag pole. The minimum flag pole size is 5/8" in order for the knob to clamp on it. It comes with the hex key (Allen) wrench for install. The mount has 2 1/4-20 tapped holes .600 apart to add a light or other accessories if needed.