Integrity Windows and Doors is one of the oldest and largest manufacturers of windows and doors in the world. The company uses Ultrex, an advanced pultruded fiberglass material, to manufacture window and door products that meet Energy Star qualifications. Integrity Windows and Doors offers bay and bow, awning, casement, double-hung, picture and polygon windows. It also features quarter-round, half-round and elliptical windows. The company provides sliding patio doors and inswing, outswing and sliding French doors. It additionally offers a range of accessories, including handles, cranks, locks, folding nailing fins, jamb extensions, drip caps and gliders. The company provides part replacement, painting, maintenance, water staining and mildew removal and troubleshooting services. It has received the Best In Class Award from the Market Resource Associates. Based in Fargo, N.D., Integrity Windows and Doors is a part of The Marvin Companies, which is a family of window and door brands for the residential, replacement and commercial markets.