Rated to protect a 2 foot radius (33 cubic feet) for up to two years, this capsule provides convenient VCI protection for smaller rifle and pistol safes.  In an enclosed container such as a MonoVault or ammo can, it is reasonable to expect much longer service.  Emits an invisible, odorless, non-toxic vapor (cleared by the FDA per Zerust literature) to protect at the molecular level.  May yellow paper products over an extended poriod of time.  We like this product for larger ammo cans and smaller MonoVaults as an alternative to VCI bags.  Also great for the tool box, tackle box, or nightstand drawer next to your secured firearm.