Selkirk 8T-CT 8" Stainless Steel Round Top Dome design excludes rain and leaves Lower skirt deflects wind for proper chimney draft 3 legs slide down over the outside of the chimney Cinch band is positioned over the legs and tightens to hold the top firmly in place "EW No. 104-1894 leg diameter (A) =8, Dome (B) 12 and height (C) = 5-1/2"