The mandrels are precision-made from high-grade stainless steel and are designed to fit both NT-3000 and NT-1000 neck turning tools, as well as most older models.
Expander mandrels are sized 0.001" larger than turning mandrels to provide a perfect fit for the neck turning process, making it more precise and easier.
These mandrels can also be used to increase case neck size up to the next caliber with the NT-EXP Expander Body.