If you are going to measure the neck wall thickness on a case this Case Neck Ball Micrometer is a MUST HAVE to get correct measurements.
If you are going to Turn the necks or just check for using Dies with Bushings you need this! Good price and if you purchase this one or any other make sure you get a good Stand to use with it. Checking a few hundred cases at a time - the stand will help out a LOT.