The Accu-Ring is a sizing/seater die lock-ring which provides reference marks in increments of thousandths of an inch (0.001"). Designed mainly for sizing dies, the Accu-Ring helps you zero in on what you want the headspace length of your cases to be. It can also allow for fine adjustments to the bullet seating depth. FeaturesDesigned to be used in conjunction with the Co-Ax Reloading PressThousandths of an inch reference marksRobust construction