The Lead Sight is a non-permanent device that attaches to the barrel of your shotgun and provides not one but four extra "beads" that swing out on hinges. Line one of these four beads up with your moving target and you are automatically "leading the target."
The Lead Sight is easy to install and is made for 12 gauge shotgun. When you're finished using it, just remove it. It will not damage your firearm. According to Gun Digest, it's perfect for new shotgun shooters, young shotgun shooters, and for building confidence.
Hat tip to Gun Digest.