The category 1 vertical 4 in vent kit provides class 1 single wall B-vent ducting for Mr. Heater Big Maxx unit heaters, ranging from 50,000, 80,000, and 125,000 BTUs. Complies with US standard (UL441) and Canadian standard (S605). Designed for vertical installation only. Kit includes 4 in x 36 in B-vent pipe, two 4 in x 24 in vent pipes, 4 in 90-degree elbow, roof flashing, storm collar, vent cap, and gas vent fire stop spacer. Other parts may be required for your specific installation needs. Please check and adhere to all state and local codes before installation.
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