Oval To 8" Round Heat-fab 22-ga Welded Black Single Wall Stovepipe Straight Boot This adaptor goes from oval to 8" round pipe This product page is selling you the photo "B" on the right for the adaptor on the rightFor the "offset adaptor" "A" in the photo on the left click here  For Vermont Castings Stoves Manufacturer's Model Number: 2858OVS