This 84049 Zero Periscope is specifically designed for use in situations where the dryer Outlet overlaps or is very close to the wall Outlet. The 2 inch by 6 inch smooth aluminium construction telescopes to handle outlets up to 5 inches distance from center to center. The 4 inch diameter draw band collar synchs down over the clothes dryer vent i. e. . The 4 inch diameter crimped fitting slides into most wall ies. Once installed, it needs only 2. 5 inches clearance behind the dryer. If your outlets are very close and you need to move the dryer closer to the wall, this vent maintains critical airflow and provides all metal performance. Clothes dryer manufacturers specify "only rigid or flexible metal vent shall be used for exhausting. Do not use plastic or metal foil vent. " installation instructions are included inside each carton. The zero periscope is built in the USA by Builder's Best.