Briley Snap Caps. Available in 12,20 and 28 gauge.
Briley snap caps offer a simple and affordable way to help protect your shotgun from premature wear or damage from dry firing.

By providing a rebounding surface for the firing pins to strike, they greatly reduce the chance of firing pin breaking. This also allows for the storing of your shotgun in a decocked mode, allowing the tension to be taken off the hammer springs and in turn increasing their service life.

As an added benefit, if you've selected the wooley snap caps, you can protect the inside of your chambers from moisture and corrosion. Just moisten the mops with briley "sport lube" and insert into the chamber of your shotgun. You have then applied a protective barrier to the inside of your gun's chamber.