The Hornady PTX Universal Powder Drop Expander for 9mm caliber features a precise 0.355-0.365 inch diameter range for optimal case mouth expansion during reloading operations.Hornady 9mm Powder Through Expander (0.355-0.365 inch)Compatible with Quick Change Powder Die systemWorks with case-activated powder drop mechanismsEliminates need for separate case mouth expander dieDirect insertion into powder die for streamlined setupPrecise diameter range for consistent case mouth expansionThis expander simplifies the reloading process by combining powder dispensing and case mouth expansion in one operation making it ideal for efficient 9mm ammunition reloading with Hornady's PTX system.