From local custom bike shop liquidation.  This pair of brackets was found in a box of parts labeled "Sturgis" and there were several other parts in the box that I could trace to a 1977 Sturgis Shovelhead 80.  I really don't know if these brackets are OEM or custom made.  1 1/2" OD and 1" ID tube steel.  Each with double hex head set screws.  2 7/8" long.  Each has off-set 4 3/8" x 2" bar.  They are both good straight condition.  14 day return policy on all of my bike parts.  See my other listings for a couple more parts from this same bike.