National Chimney M-Flex 4" x 15" Stainless Steel Standard Liner Kit btu38225 20" x 12" Adjustable Length

20" x 12" Adjustable Length Pipe

It has 12-inch 304 stainless steel burner that produces 65K BTUs of heat and glimmering flames

UL 441 Clearances 1" Minimum clearance to combustibles for 3" - 24" Diameter 8

) in a tapered design to fit most fireplaces

National Chimney M-Flex 4" x 15" Stainless Steel Standard Liner Kit btu38225 20" x 12" Adjustable LengthM FLEX standard liner kits are used for wood, oil, coal, and gas appliances. Each of our . 006" (CB) and . 005" (CBF) standard kits comes with installation instructions and a lifetime warranty. This lining kit has been installed in venting applications since 1992 and continues to be the most popular "all fuels" kit we offer. We stock 3" 8" inside diameter (ID) as well as 6" 8" outside diameter (OD) in our . 006" (CB). What's Included 1x Installation