Gzilla Awning Mount Tubular Clamps - 1 pair, 1" diameter (had it on a Gobi rack). Click the name to visit the product page. $95 new, asking $80 OBO. Designed for awning brackets, but can of course be modified for other stuff.
Black anodized 6061-T6511 USA aluminum, comes with original hardware.
Black anodized 6061-T6511 USA aluminum, comes with original hardware.