Eljer's EnduroCAST Gibralter lightweight bathtub weighs 89 lbs., making tub installation a one-man job, significantly reducing labor costs. EnduroCAST employs a revolutionary core material that boasts all the strength of cast iron without the heavier weight. Gibralter features dual stabilizer bars underneath to automatically level the tub. Eljer also reduced the amount of silica in Gibralter's enamel, enhancing bonding, gloss and depth of color, and offering resistance to flex, impact and abrasion. Eljer.