When investing in a steel roof, don't be fooled by the imitations, Double-Lock is the only time-proven roof system, it has been around for centuries! Seams MUST be finish-formed on the roof with no exposed fasteners. It has been duplicated in appearance, but not in quality! For a maintenance free roof system, Insist on the Best! Get the people with decades of experience with the best materials and craftsmanship to install your roof!