HM Cast Polyester Casting TapeHM Cast High quality, Polyester Casting Tape, Supplied as Box of 10 Rolls INTRODUCTION This is lighter than a cast, but 20 times stronger and more solid. (Fiberglass) This is more efficient than a cast when treating air permeation or moisture in hygienic way. This is easier to use than a cast. This is more eco friendly than a cast. This has better X ray permeability than a cast.