Wanted to pass on that I had ordered new single wall pipe from VentingPipe.com. From my own ignorance the pipe I ordered would not fit into the adjustable 90's I have to use with my setup. I debated contacting them and shipping it back or to buy their adjustable 90's which were twice as much as the ones I could purchase at Menards. I ended up finding a cheap pair of pipe crimpers at Ace hardware, they worked like a charm, about twenty crimps and a deadblow hammer and all was good. I did have to cut the expanded end of pipe off of one length but all is good now. So I think I did alright, saved the money for the return shipping or the other elbows and everything now goes together perfectly.