"This storage container extension kit allows you to add 3 1/2 feet to your existing West Model 1260 or 1271 storage container to expand your storage capacity. Like the regular container, the extension is made of corrosion-resistant galvanized steel that will last for decades and will not need maintenance. You can keep adding kits until you reach your desired length. Outer Material Galvanized steel, Dimensions L x W ft. 6 3/4 x 3 1/2, Center Height ft., in. 6, 6, Frame Material Galvanized steel, Style Modular, Color Galvanized steel, Storage Volume cu. ft. 135, Frame Thickness in. 18- and 24-gauge. Extends length of West Model 1260 or 1271 Item# 24758 storage container by 3 1/2 feet Kit contains everything required to assemble and attach the addition The rear of your existing container becomes the rear of the expanded container"