Durability and style-thats Integrity from Marvin. Featuring the strength and beauty of Ultrex pultruded fiberglass construction, Integrity fiberglass windows come in full line of popular styles. All Ultrex windows look incredible and their 100% fiberglass construction outperforms and outlasts vinyl, aluminum and composite materials. Wood-Ultrex windows combine an authentic wood interior with a virtually indestructible fiberglass exterior. Factor in our IMPACT Products for coastal applications and there is no doubt Integrity windows are Built to Perform.