Don't adjust dies when switching calibers. These precision tool holders hold your dies in perfect alignment making caliber changes quick and easy. This toolhead fits both the XL750 and the XL650 machine. The toolhead is the final link between your dies and your press so it only makes sense that quality is extremely important. With over 100,00 USD of dies, powder measure, and other accessories mounted in your toolhead, don't you want to know it's the best available. These toolheads are made to the highest standards. The are CNC machined from 6061 aluminum, which is much stronger and has less flex than a cast toolhead.