The Dri-Eaz LayFlat Ducting, 500' Roll, 108746, is a versatile way to extend the reach of drying and ventilation. The roll is made of 4 mil polyethylene, which is resistant to moisture and most chemicals, and lays flat so it can be easily rolled up for transport and storage. The Dri-Eaz LayFlat Ducting, 500' Roll is for use with 8" duct outlets and can be cut to the required length.