Duct tape, or duck tape, is a polyethylene, reinforced, multi-purpose pressure sensitive tape with a soft and flexible shell and pressure sensitive adhesive. It is generally silver or black in color but many other colors have recently become available. With a standard width of 1+7⁄8 inches (48 mm), duct tape was originally developed during World War II in 1942 as a water resistant sealing tape for ammunition cases. Permacel, then a division of Johnson & Johnson, used a rubber-based adhesive to help the tape resist water and a fabric backing to add strength. It was also used to repair military equipment quickly, including jeeps, firearms, and aircraft because of these properties.