The Hornady PTX Universal Powder Drop Expander comes in a variety of diameters including .355 .357 .400 .430 .451 .452 .475 .500-inch and others. This drop expander is used for reloading using the Quick Change Powder Die as well as the case-activated powder drop.With this expander separating the mouth on the case expander die is no longer required. The expander is simply inserted into the powder die and the powder drop then sits on the surface with the powder measure on top. The result is an expanded case mouth to the desired diameter.