The Marvin Ultimate Insert Double Hung Window adds quality craftsmanship, beauty, and energy efficiency to your home without compromising architectural integrity. Its frame-in-frame design is built precisely to seamlessly fit into your unique window opening, so there’s no need to remove the existing frame or disturb the exterior or interior trim of your house. Marvin’s Ultimate Insert Double Hung windows always fit perfectly into your existing space, and appear completely integrated into your home.