Round Hole Duct, 4 Inches x 4 Inches x 6 Feet, Black, Base and covers sold separately, Made of lead-free PVC, UL Recognized continuous use temperatures up to 122 Degrees Fahrenheit (50 Degrees Celcus), UL94 Flammability Rating of V-0, Conforms with NFPA 79-2002 section 14.3.1 requirement for flame retardant material, Provided with mounting holes.