Every reloader should know exactly how much your Full Length Sizing Die is pushing back the shoulder. With the Case Gage Depth Micrometer you can do just that. The Depth Mic allows you to slip the micrometer perfectly over the top of the gage with your case inserted into the gage and take a measurement. Graduations of .001 comes with a Gage Block. One size works for all L.E. Wilson Gages , 50 BMG Gage may not be compatible depending on if you headspace is over max dimension. We are working on a solution for this.