Our Nova Carbon blades do replicate the pushrod that was present on the ROTS carbon blades. However, on the original props, those pushrods were simply glued or press-fit into the carbon tube with no fasteners needed. For Nova Carbon, we wanted the user to be able to swap between a long screen-accurate pushrod, or a shorter one that could be adapted (using the included parts) to fit in a 1-inch or 7/8-inch blade holder. So that's why we added the set screws. They weren't on the originals, but appear on Nova Carbon for that reason. It's our one minor departure from the originals, but in my opinion is a nice callback to the Ep1 and Ep2 blade attachment method, and gives Nova Carbon a nice kinship with those blades.