The Redding Case Neck Concentricity Gauge is a great tool for reloaders to use to sort their brass by thickness and uniformity of case necks. Many of today's top competitive target shooters measure and sort their brass for consistency and uniformity trying to get everything with their ammunition to be the exact same. Taking the time to do this not only helps to reduce any variations but it also gives the shooter the piece of mind to know that their reloaded ammunition is the best it can be. Accuracy: .001" Features: Measures cases with flash holes as small as 0.060"Can be directly mounted to reloading benchIncludes: Two mandrels to measure cases from .17 to .338 Caliber22 caliber and 30 caliber pilot stops (To measure other calibers reloaders must purchase the appropriate Redding Case Neck Gauge Pilot Stop, sold separately)