Our Rubber Stovejack withstands temperatures of up to 700 degrees. It is made with a thicker ring around the pipe to divert water around the stovepipe. The Stovejack can be sewn in, the shape of the hole is oval.
Outer Flange Measurement of the Rubber Stovejack* This is a close approximate measurement of the outside diameter of the rubber stove pipe flange. Because they are custom made each one they can vary just slightly: It is 17 3/4 inches wide and from the top pointed ridge to the bottom is 17 1/2 inches. It comes with a standard 5 inch hole but can be ordered to be a 4 inch or 6 inch as well.