JB Sash & Door’s 3,000-square-foot Marvin Windows and Doors showroom and design center. Contractors, architects and homeowners can experience the innovative products from Marvin and Integrity, and leading door companies including Therma-Tru, Upstate Door, Simpson, TruStile and Jeld-Wen. Carrying Boston's largest collection of doors and window displays features a one-of-a-kind showroom with interactive displays, a Marvin Windows and Doors Personalization Station and extensive consultation and design space.