Depending on your unit, there are a few places the manufacturer information may be located. The first location would be a metal plate that is on the left or right side of the smoke shelf bracket, right at the top of the fireplace front opening. The next place would be just on the inside of the opening, behind the fireplace screens on the left or right side. The last location would be in the void space underneath the fireplace floor. This can be accessed either through the front of the unit's louvers or through a removable floor panel underneath the bottom refractory.
If you do not have the manufacturer or model information of your fireplace, then we can offer universal replacement panels. We carry options for both woodburning fireplaces and gas fireplaces. If you have a woodburning fireplace (or a fireplace that originally burned wood but now burns gas), we do offer some universal refractory panels that will work for your woodburning fireplace. Please see the following links:
One 24"h x 28"w Panel
Two 24" h x 40"w Panels
These panels are about 3/4" thick and can be cut down to the size you need with a masonry blade or tile saw. They are suitable for use as side, rear and floor panels inside any manufactured woodburning fireplace.
If you have a fireplace that is only listed to burn gas (vent-free, direct vent or B-vent), please see these universal panel options:
El Dorado Decorative Brick Firebox Panel
Seville Decorative Brick Firebox Panel
Florence Decorative Brick Firebox Panel
Each of these panels measure 22.5" wide by 19.5" high and they are 1/2" thick. They can be cut to the size(s) you need.