Select options 5″ x 16, 18 & 20 oz. Copper Smooth Round & Corrugated Elbows $27.50 – $29.50 Smooth elbows will have one end expanded for ease of installation The average downspout installation requires 2 elbows at the top and 1 at the bottom. If you are connecting your downspout into a drain tile, the elbow at the bottom is not necessary. The offset is the measurement of 2 connected elbows. The 40 degree elbows have an offset from 5″–10″. 72 degreee elbow offset is 11″. For offsets greater than 11″ extra downspout will be needed. An overhang of less than 5″ will require 2-40 degree elbows. This elbow combination also works when making a transition around a ledge of other protrusion. You will need to reduce the size of the opening on the elbows and downspout when installing the downspout system. (See Installation Tips below.) Note: 16 oz. smooth elbows will have folds in the bend; 18 oz. welded seam smooth elbows are completely smooth.