Set of six, 3.6 inch dia (3 inch double wall) stovepipe heat exchanger / radiator rings that extract heat from the hot stove pipe and radiate the heat into the room. They will fit 11.5 inch circumference typically used with pellet and corn stoves. They work on the same principle as the aluminum fins on a motorcycle engine. They make close contact with your stove pipe and conduct more usable heat from the hot pipe to be released into the room. They, in effect, increase the surface area of your stovepipe between the stove and the chimney, allowing more heat to be radiated and released into the room. You get one lot of 6 radiators. They are made of 28 gauge aluminum, 1 ½ inches wide. They attach quickly and easily to your stovepipe and will work with any heat source. No screws or tools are needed. The ends lock into each other. It takes about 2 minutes to attach all six radiators. Free Heat. Each radiator has 6 loops that are 2 inch x 1.5 inch…that is 18 square inches of sheet metal. Six rings gives the equivalent of 108 square inches of sheet metal. That is equivalent to a 10 inch x 10 inch hot sheet of metal.. So, in effect, by installing this set of 6 bands, you create the equivalent of a 10 inch x 10 inch sheet of hot sheet metal, 500 - 700 degrees, radiating heat from both sides of the sheet into the room before it escapes out the chimney. That is like a small space heater itself and it is free Heat. See my other listing for 3, 4,5,6,7,and 8 inch diameter. They will last a lifetime and may be re-used if you replace the stovepipe. They never need maintenance. Guaranteed to draw more heat from the stovepipe and pay for themselves in a short time. Put on as many bands as you wish. This set of 6 will cover a 9 inch length of pipe. . NOTE: The length of stovepipe in the picture is not part of the sale.