It's about 10 inches I think. It's buried in my boat shed at the moment, but the specs on the NRS website look like 10 inches. It already has the hole in the side where to screw mounts the NRS decking to the LoPro so that worked perfect for the clip to secure it. This would also work as an umbrella stand.
I used the flag pole for one trip, then decided I didn't care for the flag whipping around in the wind on the boat all that much. Now I just hang my flag off the perimeter line on the raft. The LoPro holder did work very well though. You can move it and adjust the angle easily. It was scavenged off a side deck that I no longer used.
"We are all visitors to this time, this place. We are just passing through. Our purpose here is to observe, to learn, to grow, to love....and then we return home."
Australian Aboriginal Proverb