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 12 in. vent pipe, 4 in. 45° 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.

• Category 1 horizontal 4 in. vent kit for use with Mr. Heater big maxx or heatstar by enerco brand unit heaters ranging from 50,000, 80,000, and 125,000 BTUs
• Stainless steel 4 in. sealed ducting meets new category 3-certifications
• Includes: 4 in. x 6-19 in. adjustable pipe, 4 in. x 12 in. vent pipe, 4 in. 45° elbow, 4 in. wall thimble, 4 in. termination tee, screws, and silicone
• Complies with US standard (UL1738) and Canadian standard (S636)
• Kit provides the pieces needed for an average installation - additional pieces may be needed