"Auto Bench Prime. Compatible With: Large & Small Primers. The easiest, most convenient bench mounted priming tool on the market. Symmetrical design allows effortless right or left hand operation. Comfortable lever with just the right amount of mechanical advantage effortlessly seats even the most difficult primers with just finger pressure. The perfect mechanical advantage to feel the primer seating completely home into the primer pocket. Includes priming assemblies for large and small primers. Made of a water clear tough polyester material that allows you to monitor the primers passage from the tray to the primer pocket. Change primer size or shell holder in seconds. Includes the new folding tray—go from box to priming in seconds. Tray has a built-in primer flipping feature allowing direct filling from today's large primer boxes. The tool mounting holes are spaced for the Lee Bench Plate system (#90251) or can be mounted directly to your workbench. Uses special, but inexpensive priming tool shell holders, so there's no need to endlessly swap press shell holders to prime."