42" builders woodburning firebox. Firebox includes heat circulating louvers, cast-iron grate, wire mesh screen in hidden screen pockets, and a full brick liner. Approved for use as a wood burning fireplace or for use with vented gas log sets, or vent free gas logs. Accessory hood and FMI venting pipe must be installed when using vent-free logs. Approximate product dimensions: 48" W. x 44-1/2" H. x 22-1/2" D. IHP venting pipe must be installed, which have been designed to fit and tested for this fireplace system.