Vapor phase corrosion inhibiting products (VPCI) use molecular compounds in vapor phase to prevent corrosion in machining, milling operations, and in military preservation. The chemical compound actively attaches to metal to prevent corrosion.

Vapor phase products work as a gas rather than requiring physical contact; plastic wraps and foam pads emit molecular protection for metal surfaces without being in direct contact. For longer-term preservation "Emitters" are used. These emit larger amounts of the corrosion inhibiting molecules than the other products alone.

These products work even in the presence of water. Since water damage is more than just corrosion we recommend that VPCI be used in conjunction with other preservation packaging like; gusseted vapor barrier bags, shrink film, and desiccants.