This Pleasant Hearth Fenwick Fireplace Glass Door reduces heat loss up the chimney by 90-percent when the fireplace is not in use, plus adds style and function. When you're not enjoying a fire, simply close the smoked tempered safety glass to minimize heat and cool air loss. Fireplace openings 30-Inch to 37-Inch wide and 22-1/2-Inch to 29-1/2-Inch high. For masonry fireplaces only. Not for use on pre-fabricated fireplaces. U.S.A. That equals a year round energy savings when fireplace is not in use. The Fireplace Glass Doors all come with easy grip handles, hidden damper control knobs for air flow control and heat resistant thick insulation. Always keep mesh panels closed and glass doors open when fire is burning in fireplace. Before you buy, measure the front opening width and height to choose the correct size. Product dimension: 38.75 L x 2.00 W (depth) x 28.00 H