"rip-stop" silver jacket flexduct has a metallic, polyester-vapor barrier with a special "rip-stop" scrim reinforcement. Temperature range is -20F to 200F intermittent Oversized core to fit on collars and register boxes Most federal, state and local codes and standards Also available in boxes Meets UL Standard 181 ASTM C-518 ? Dynamic HUD/FHA standards 515.2.1 Paragraph B NFPA standards 90A and 90B