Here's a SportRack Modular H #A30954 modular 4 bike hitch system HEAD ONLY. SportRacks Modular system came in 2 parts, the part that held the bikes (this one) and the lower part that fit into the hitch. This part is NOT INCLUDED. This is a replacement set up for your existing rack, or to make a custom rack. The quick release mount screws into an upright tube. This part measures 1-1/4". 

I know this sounds confusing, but if you have an older SportRack, you'll most likely understand. Great to replace your old worn out trays. I also sell the individual bike trays separately. 

New in box, never removed.