MoistureGuard Centerfire Rifle Plugs. Pack of 3 fits calibers 222-223, 243, 308, 7mm-08, 270, 30-06. Using Volatile Corrosion Inhibitor Technology. Protects all metals from rust and corrosion. Place in chamber or mount in gun cabinet or safe to protect gun barrel. Hangs in gun safe for up to 30 cu. ft. of protection (mounting clip included). Use as a snap cap.