These elbows are a thing of beauty and a testament to the true engineering behind this system. The 70° angle is perfect for most buildings. The elbows are conical, and come with a male a female end that fits perfect every time, always overlapping 2". The double seam is turned outside-in halfway through the arch, making the fit to elbows, outlets and downspouts extremely snug. There is no need for caulking or putting any rivets or screws into the system. In most other systems caulking and putting screws in the flow of water results in debris being clogged, increasing the risk for leaks.