Ultramount top plates. One of the important design elements of the Ultramount press riser system was to be a modular, universal system. So, say you start out with a Dillon 550 press, then decide to roll up to a 650, no problem, all you need to do is purchase the top plate for the 650 and you are good to go. Couple years down the road you decide to go Rockchucker single stage, no problem, grab the top plate for the chucker and you are set.
All top plates come with quality hardware required to mount the specific press.
Note: These are top plates for standard dedicated Ultramounts, not the quickchange top plate system. They are right (Here)