Kit includes everything that you need for quick, easy dryer vent installation in your RV. A 4 in. louver and tailpiece with curved, paintable, and UV protected louvers open easily for maximum exhaust flow. The metallic flex duct is fire resistant for safety. Two, worm drive screw clamps make tight duct connections easy. Kit includes 4 in. louver vent flap and bracket, 4 in. tailpiece, 2-4 in. screw clamps, 4 in. inside round collar and 4 in. x 2' metallic flex duct. 1 per box.