I appreciate this site so much. I had posted a few days ago about my short chimney height. after reading more posts on here I found a few threads about installing a transition plate on top of the masonry chimney to go from flex liner to class A pipe ontop of chimney to extend it. The dealer I am going to buy my buck 74 from sells duravent brand. After alot of research and calling their tech support , the transition plate they sell is not for flex liner, it is for rigid double wall liner. so I have been looking at the rockford rock-vent brand which sells exactly what im looking for, and ventis brand sells a transition plate which looks very much the same as the rockford stuff. I saw a comment on a thread that olympia makes them both, but I have not found that said anywhere else. the prices for everything I need are about the same for both brands. Does anyone have any experience or recommendations on which one of the two to go with. or the best place to buy the ventis through if I would go with that brand. thanks again.