The Lyman Neck Size Die with Carbide Expander Button is a new addition to the Lyman family and is quickly becoming a must-have item among serious reloaders. This neck size die has been precision crafted with a hardened steel body and includes a super-strong carbide expander button. With the addition of the carbide expander button, the Lyman Neck Size Die reduces case stretching, which increases your case life and gives you greater accuracy. The button floats freely on the rod, which allows it to self-center inside the case neck while the button itself passes through.