YOST 12" Master Elbows are a perfect fit for a 12" overhang, just insert a regular "A" Elbow (sold separtley) into the end. If you have a 11" overhang or less just snip off the difference on the long end of the Master Elbow and insert your "A" elbow, no need for crimping. Master Elbows reduces waste, seams and time. (.019 thickness)