Sure-Temp elbows. 15 deg. elbow can be used for fixed offsets of 15 deg. slope or in pairs for offsets adjustable from 0 deg. to 30 deg. slope. The 30 deg. insulated elbow can be used for fixed offsets of 30 deg. slope. Greater angles are prohibited by UL standard 103 and by the terms of the product listing. Includes 2 elbow and interior resupports in 1 box. Add locking bands that allow 360 deg. rotation and lock the components together in place at the exact offset required.