The Replacement Hitch Cup Assembly for Ultra-Fab 5th Wheel King Pin Tripod Stabilizers part # UF19-001056 is made of aluminum. I called my contact Ultra-Fab to confirm this. This cup is used on both the Ultra-Fab 5th Wheel King Pin Tripod Stabilizers part # UF19-950001 and part # UF19-950200. view full answer...