Ply Gem. Premium 1000 Series vinyl windows, which are Energy Star-labeled and NAHB Research Center Green Approved, feature R-Core insulation in the frame for added efficiency; the Energy Package upgrade includes R-Core in the frame as well as the sash along with Interforce II fiberglass reinforcement in the meeting rails of double-hung and sliding windows. The windows include a flush-mount locking system and are available in double-hung, sliding, fixed, and geometric models. A darker beige has been added to the line's color options. www.plygemwindows.com.