This is made for a 6-in diameter pipe. This DuraVent DuraPlus 6DP-VC 6 Inch Diameter Stainless Steel Round Chimney Cap provides protection from downdrafts. Also has a built-in cage which I believe is for spark arresting. The base of the cap is 12" in diameter. the inner stove pipe holding part is 6" in diameter and it is uncrimped. Made with high-quality stainless steel, metal, and steel materials, this chimney cap is built to last. It fits a 6 in (152.4 mm) stove pipe diameter. I purchased this about 4 years ago and never used it it has a few extremely light scuffs from being moved around in the garage. Nothing you will ever see from down below. Please view all the photographs under magnification and read the specifications on the body of the item shown in the photographs if you have any questions please ask before making a purchase thanks a lot. This is for 6-in diameter pipe stove pipe.