VCI bags, also known as volatile corrosion inhibitor bags, are made of special materials that release a rust-inhibiting vapor to protect metal surfaces from corrosion. These bags are designed to prevent rust and other forms of corrosion from developing on metal items during shipping and storage. They are commonly used in the automotive, aerospace, and military industries to protect metal parts and equipment from corrosion. VCI bags are available in various sizes and types to suit different applications, and they are an effective and cost-efficient way to protect metal items from rust and corrosion.