The Lambro 4 In. ABS white plastic quick fit clothes dryer exhaust elbow is ideal accessory for venting a clothes dryer. This elbow is used for clothes dryer exhaust venting applications when connecting the flexible duct to the clothes dryer. The elbow labeled A has a rubber gasket that slides onto the dryer exhaust outlet securely without the need for a clamp. When using semi-rigid duct, simply thread the elbow into one end of the duct (no clamp needed). The kit includes a 4 In. worm gear clamp to connect foil flex duct to this elbow. This elbow allows you to inspect and clean your clothes dryer vent duct without the need of tools to disassemble and assemble.