The Klickfix system is the 0211ST or the 0211VO(L). They hold only 5kg, and judging by the way they look, it looks likely that Klickfix might actually have built the luggage truss sold by Tern and Dahon under their own brand.
16mm looks like the distance between the two nuts on Tern bikes. Maybe Klickfix uses a drawing common to Dahon and Tern?