Vent-Free, Low Profile Firebox By Surefire features a large, high front opening, with a spacious deep hearth * Made for rooms with higher ceilings, this unit features a full 42" wide opening, a low profile hearth and traditional herringbone firebrick liner * The opening dimensions required for this unit are: 41"width; 40.15"rough opening height; 38"finished height; 21.5"depth * 99.9-Percent Efficiency; Saves on high energy costs yet delivers maximum heat output * Complete with Screen and Heat deflecting mantel guard to protects mantels