Chimney Liners, For Nominal Duct Diameter 4 in, Outside Diameter 4 in, Overall Length 5 ft, Maximum Pressure Rating Not Applicable, Maximum Temperature Rating 470 Degrees F, Maximum Airflow Not Applicable, Material Aluminum, Material Grade 3003, Compatible with Fuel Type LP Gas, Shape Straight, Color Silver, End Type Snap Lock, Includes Not Applicable, Interior Texture Corrugated, Number of Plys 1, Wall Thickness 26 ga, Product Type Gas Vent Pipe, Inside Diameter 3 in, Connection Type Snap Lock The Ameri-Flex single wall connector system is UL Listed as a vent connector for installation as specified in the National Fuel Gas Code (ANSI Z 223.1, NFPA 54), NFPA 211, and other model codes such as Uniform Mechanical Code, National Mechanical Code, and Southern Mechanical Code. The flexible pipe.