and then heres the second part DIY, were gonna be making the diffuser using my template. took me 2-3 hours ENJOY heres a roll of sheet metal, i have no idea what hot dipped galvanized flashing means, there were several types of roll to buy, i just went with the cheap one . some metal to metal fasteners, 1/2 inch long and u need TWO of those 90 degrees bars, i made a miscalculation and ur gonna nee