This tool provides a quick and easy method for sorting cases by neck wall thickness and uniformity. It allows you to accurately measure the neck wall thickness of cartridge cases and assess their uniformity. Two mandrel sizes are included, enabling measurement for all cases from .17 Cal to .338 Cal, including those with small (.060) flash holes. For added convenience, the mounting base can be directly attached to your reloading bench or alternatively, you can use the Redding No. 30520 double "C" clamp for secure placement. This tool ensures precision and consistency in your reloading process.