Air Systems SV-18912-B Saddle Vent, 12 in. dia., Black 

One extremely efficient way to transport good air in and bad air out is a corrosion-free flexible duct system, which can be found in our confined space ventilation ducting equipment section below.

Take a look at the features for Air Systems International Saddle Vent. Length: 52", Diameter: 12".

Specifications 

Diameter: 12"
Length: 52"
Color: Black
Standards: NFPA
Construction: Polyethylene
Item: Saddle Vent
For Use With: Conductive Saddle Vent
Country of Origin (subject to change): United States