The RF571 is a roof flashing for the SL1100 and SL400 Series chimney pipe, for roofs with a 7/12 to 12/12 pitch. It seals the roof penetration around the chimney pipe and sheds water away from the opening. Per the manufacturer drawing, the collar is 15-1/4 in. (387 mm) wide and the base measures 39-7/8 in. x 28 in. (1013 x 711 mm). Choose the flashing that matches your roof pitch. Always confirm the pipe size, approved components and clearances in your fireplace, stove or chimney installation manual before ordering. For lower-pitch roofs, use the RF570 (0 to 6/12 pitch).