We manufacture the products we sell. We will not be undersold. At Lang Exterior, we manufacture the replacement windows and patio doors. We have been in business since 1953. Currently, we make more than 30 types of windows and patio doors and other vinyl products at our Chicago, IL, location. When you choose experience like ours, you can bet you'll get exactly what you need. In addition to selling windows and patio doors, we offer vinyl window glass repair directly to the public. Call Lang Exterior or visit the website today!