The category 3 horizontal 4 in vent kit provides class 3 single wall ducting for use with Mr. Heater Big Maxx unit heaters, ranging from 50,000, 80,000, and 125,000 BTUs. Complies with US standard (UL1738) and Canadian standard (S636). Designed for horizontal installation only. Kit includes 4 in x 6-19 in adjustable pipe, 4 in x 12in vent pipe, 4 in 45-degree elbow, 4 in wall thimble, 4 in termination tee, screws, and silicone. Stainless steel is required for horizontal installations per new category 3 certifications. Other parts may also be required for your specific installation needs. Please check and adhere to all state and local codes before installation.Note: This product may require up to 2 additional days for order processing prior to shipping

For additional information on this product, please see the Product Documents section for all downloadable user manuals, installation guides, brochures and warranty statements.