Osburn 5" x 10' Insulated Flex Pipe for Fresh Air Intake

Ten feet of insulated 5-inch flexible pipe for the outside-air connection on the Osburn Horizon, between the fireplace's 5-inch adapter and the outside termination — the length Osburn recommends as a minimum, with a P-trap loop in the run, to avoid condensation and rust. The Horizon manual requires the intake pipe to be HVAC type complying with ULC S110 / UL 181 class 0 or 1 and to withstand 250 °F; clamp it at both ends (aluminum tape gives a better seal). On the Horizon, 5-inch pipe is for runs under 20 feet with no more than two bends. Pair it with the 5-inch termination with clamps and the 5-inch airtight intake register. $75.