Deflecto Aluminum Duct with Connectors, Semi Ridgid, Flexible , 4" x 2', Silver (AM42) N/A Made in the USA or Imported Made with 30 gauge aluminum for strength 4 in. diameter fits compatible ducts Flexible for easy installation Features a maximum temperature rating of 284 degrees Fahrenheit Ideal for connecting 2 ducts 4 inch Dia X 2-feet Length Fire-resistant Aluminum Flexible Aluminum Duct