6 Stovepipe Heat Reclaimer Radiator Rings, 4" Dia wood stove pipe accessories Reclaims and radiates heat from your stovepipe to your room Made from 28 ga. Aluminum, 1 1/2" wide. Draw more usable heat from your stovepipe. Fits 4 inch diameter stovepipe. (13 inch circumference) They pay for themselves in a short period of time. Easy, Snap-on installation. They will last a lifetime. They never need maintenance.