Pella 250 Series white vinyl sliding window (OX fixed/vent configuration) measures 58.75"W x 34.25"H rough opening. Features Low-E 180/i89 glass with argon gas fill rated for high altitude use. Solar heat gain coefficient of 0.50 and visible transmittance of 0.61 for energy efficiency. Annealed glass with left-to-right vent operation. Includes screen and all hardware. Arrives in original box in like new condition. Ideal for Denver's climate and altitude requirements.