The corrugations in these round galvanized elbows give the elbow more rigity as well as room for expansion due to ice. Each elbow is crimped to fit inside other elbows and downspouts. The female end easily fits over the half round "B" style outlet tube. Round corrugated galvanized elbows are available in 26 gauge in 3", 4", 5", and 6" diameters.
Flat seam design can occur due to stretching of diameter when forming. This can permit capillary action to cause drips from seam when used in lower position with water flow on seam. This may require sealant or solder to prevent drip.