The RCBS 18212 is a 3-Die Carbide Set from RCBS, perfect for straight-wall rifle and pistol cases. It includes a Carbide Sizer Die that sizes the case and carries out the de-priming process without the need for lubrication, thanks to the handy carbide sizer ring.Along with it, the set contains an Expander Die that expands the case to the proper diameter in order to accommodate the bullet, and it also imparts a necessary flare or bell to the case mouth for more effective bullet feeding.Completing the set is the Seater Die, which not only seats the bullet but also roll crimps it, ensuring a polished finish every single time.