THERMAFLEX S-TL, NON-INSULATED HVAC DUCTS ARE IDEAL FOR RESIDENTIAL DRYERS, BATHROOM APPLICATIONS, CLEANING ROOMS AND OTHER AREAS WHERE INSULATED DUCTS ARE NOT REQUIRED. THESE FLEX DUCTS ARE FOR LOW TO HIGH PRESSURE HEATING AND COOLING SYSTEMS. THEY FEATURE A HEAVY DUTY FIBERGLASS CLOTH FABRIC THAT IS BONDED TO A CORROSION RESISTANT SPRING STEEL WIRE COIL FOR LONG LASTING DURABILITY. DUCTS WILL NOT UNRAVEL WHEN CUT AND HAVE A SELF-EXTINGUISHING INNER CORE THAT WILL NOT SUPPORT FLAMES. TEMPERATURE RANGE IS FROM -20F TO 250F. DUCTS MEASURE 2-20″ IN DIAMETER. GREENGUARD CERTIFIED.