Maybe 20 years ago we had a zero clearance fireplace installed. This was not a pre-built but rather a modular fireplace that I have no idea of the brand. It had a large stainless steel firebox that was framed in and concrete back wall, side walls and grate. It was designed to not use a grate but rather build the fire on the raised prefab floor. It has a damper but that is on the top of the triple wall pipe on the roof. It has a lever to change the air input from under the floor to inside the room. After it was all built, the large stainless steel box was filled with vermiculite surrounding the concrete fireplace. Any ideas what this fieplace brand might be? It has been a great fireplace and my daughter wants one. Picture would only show the fireplace as all the rest is inside the framing.