It's only to carry a pillow and a cellular blanket (essential for a happy wife) and we load all the serious weight in the panniers.
In case anyone was wondering it's actually an (almost) homespun effort, with a little outside help made from 3/8" dia 14swg stainless steel tube.
Copied shamelessly from the Givi original, (with a couple of tweeks) on my old Pan.