The DuraTech 8 Class A Chimney Pipe Stainless Steel 15 Degree Elbow Kit is used for offsets around obstructions such as rafters, ridgepoles, or joists. May have two pairs of elbows, if needed. Offsets greater than 30° are not permitted in accordance to UL 103 standards. Elbows swivel 360° at base (angles are not adjustable). A pair of elbows is required to return an offset chimney back to vertical. Elbow kit includes 2 elbows and 1 elbow strap.Elbow by Angle: 15 (degree) Fuel Type: Coal, Gas, Oil, Wood Includes: (2) Elbows, Elbow Strap Material: Stainless Steel Pipe Class: Class A Pipe Inside Diameter: 8 Pipe Shape: Round Style: Functional UL Listed: Yes Vent Construction: Double Wall Weight: 23.1