Dundas Jafine FD420ZW Flexible White Vinyl Duct, 4-Inches by 20-Feet, 4" x This flexible duct is ideal for general purpose exhaust applications including bathroom fans and surface mounted humidifier units Heavy duty for long reliable life Should not be used for dryer venting Color: White Vinyl duct. Size: 4 Inch x 20 Feet Product dimension: 13 x 4.1 x 4.1 inches