Compatible w/all Toyostove models, this flexible extension pipe is for use of relocation of exhaust pipe higher or "up the wall," length capacity for extension installation of 11-3/4" The following limitation must NOT be exceeded: 1. The total length of extension pipe between the heater and the outside tip of the flue pipe must not exceed 10 feet each for the air intake pipe and the exhaust pipe. 2. Neither air intake pipe nor the exhaust pipe may have more the 3 elbows, counting the elbows at the heater. The air intake elbow supplied with the heater and the integral bends in the flue pipe are not counted as elbows.