McKesson 4-inch Fiberglass Cast Tape uses a water-activated resin that lets you control the working time according to application needs. Its high and early strength allows for weight bearing in 20 minutes and provides a durable cast with less chance of breakdown or the need for costly repairs or replacements. This cast tape also stretches to conform well to contours for a more comfortable, better-fitting cast while its porous weave allows the skin to breathe.