These have a smooth inside diameter as well as strength and durability. These are light weight and designed for maximum air flow and can be used with wide range of Blowers, Portable Evacuaters, Fans, Printing Machines and Dryer Machines for both Positive and Negative Pressure. Fire Resistant and Antistatic Quality Hoses are available. These are Weather Resistant Hoses. Flexible PVC Hose made with continuous Spring Steel Wire reinforcement Helix between Polyester Fabric Coated with PVC on both sides.