Curt Receiver Tube Adapter (1-1/4" to 2" Shank, Not for Towing Use, 6-1/4" Length) #45785CURT hitch adapters can be used for many different purposes when hitching up a trailer. Whether a ball mount shank is too small or too large to fit into a receiver tube, a CURT adapter can make up the difference. Our adapters are built with exceptional strength and designed to be precisely fitted for their application. We carry trailer hitch adapters to accommodate both receiver tube openings and shanks of 1 1 4", 2" and 2 1 2" dimensions. CURT