Is that a male female elbow like an appliance adapter? I'm hoping for now I can grind down sharp edges on the cut damper my install will have to be done relativly quick and then this summer I will take it out to do some cosmetic work and touch ups on whatever I have to roughly fab to get it functional my nc-30 is going to have to start throwing the heat early. Unless we just suck it up and stick with the current setup until warm weather hits. But I would like to have this beast working for me now. Got a feeling if I wait to install I'm gonna go crazy waiting on next winter to come