Dillon Precision Bullet Feeder Bullet Drop Die - 10MM / 40 (0.400") Caliber

Photo is for reference only. This is the Dillon Precision Bullet Feeder Bullet Drop Die.  This allows you to keep the die set up in your Dillon 750 or 1100 toolhead.  And move the bullet feeder to load another cartridge.  Like moving from 9MM to 38 Special