The DuraVent DuraPlus 6 In. Class A Chimney Pipe Galvanized 30-Degree Elbow Kit (9066KIT), which includes 2 Elbows and 1 Elbow Strap, is used for offsets around obstructions such as rafters, ridgepoles or joists. 6 in. and 8 in. DuraPlus may have 2 pair of elbows if needed. Offsets greater than 30 degrees are not permitted in accordance to UL 103 standards. Elbows swivel at 360-degrees at base (angles are not adjustable). A pair of elbows is required to return an offset chimney back to vertical.