Midwest Industries does not provide that information.
Good question- I bought this because of the low advertised height, but I don’t see where this 0.388 comes from. I measured 0.450” above the rail flat top to the folded sight at its highest point.
It works well on my AR-10 with a reasonably low profile optic system. The “intermediate” aperture diameter measures 0.150” and is the perfect size in my opinion.