Browning's VCI (Vapor Corrosion Inhibitor) Two-Piece Gun Sock seals out moisture for both halves of your shotgun. VCI penetrates into the smallest crevices where oils cannot reach, driving out moisture. Provides full protection by forming an enclosure around your firearm from muzzle to buttstock. The VCI Sock, when used in a safe or cabinet, will offer additional protection to all metal items in the enclosed area. Some of us store our take-apart shotguns in two pieces to save some space (they can fit on a shelf). Or you might be transporting your over and under in a fitted or hard-shell case, where each component can be protected from rust or moisture throughout the trip.