3M Scotchcast Plus Casting Tape - 2" x 4yd is strong, lightweight, water resistant and hard wearing that combines the benefits of a synthetic tape with the handling ease of plaster. It is composed of knitted fiberglass fabric impregnated with a water activated polyurethane resin. Exposure of casting tape to moisture or water initiates a chemical reaction which causes it to become rigid. This tape conforms well to contours, improving cast fit thus increasing patients comfort and mobility.