3 in. MAMMO MONSTER! (Outside Pipe Diameter 3.5 inches)
No need to remove the sheet metal or the shingles. The long 3 in. MAMMOTH MONSTER aluminum collar fits nicely on roof vents. Tar should be removed from the pipe so that the collar can slide down to meet aluminum. So EASY. Now the leak is fixed. An EPDM rubber ring will outlast neoprene rubber 2 to 1.