They are just another gimmick looking for a market niche, but folks will purchase them regardless. Why would you buy some piece of plastic to stick down the barrel of your weapon, just to reassure yourself that the weapon could be empty..?? Good Lord...just perform a chamber check...check the magazine well to be sure it is empty and go to your designated dry practice area, sans any ammo. How simple is that..?? Learn how to dry practice safely and correctly and you will never need junk like that.