6 inch dia (19" cir) stovepipe heat exchangers (set of 6 snap-on bands) stovepipe reclaimer / radiator rings that extract heat from the hot stove pipe and radiate the heat into the room. They make close contact with your stove pipe and extract more usable heat from the hot pipe.. Just like the aluminum fins on a motorcycle engine, they increase the surface area of hot, exposed metal and allow more heat to be radiated and released. Made of 28 gauge high thermal conductivity aluminum. Attach quickly and easily to your stovepipe, no screws or tools are needed. The ends lock into each other, taking about 10 minutes to attach all 6 radiators. The bands conduct heat from the points of contact on the stovepipe to the loops in the band where the heat is released into the room. Each radiator has 10 loops that are 2 inch x 1.5 inches…that is 30 square inches of sheet metal. 6 rings gives the equivalent of 180 square inches of sheet metal. That is equivalent to a 10 inch x 18 inch hot sheet of 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. Put on as many bands as you wish. This set of six bands will cover a 9 inch length of pipe. . NOTE: The length of stovepipe in the picture is not part of the sale.