This 12 gauge to .410 shot shell adapter is CNC Machined from Alloy steel that will allow the conversion of your 12 gauge shotgun to the fire the .410 caliber shot shells. By merely pressing the .410 cartridge with your finger, into the adapter you can then then insert it into your shotgun. The purpose of this adapter will allow you to hunt small game with your current 12 gauge shotgun. Another application would be for training a youngster or the lady of the house using a 12 gauge shotgun with the recoil greatly reduced. You can also buy enough inserts to cover you magazine capacity so that you can keep the gun fully loaded.