Mr. Heater MH200CVX 200,000 BTU Propane Convection Heater w27.125 Mason-Lite offers several damper options:

Mason-Lite offers several damper options: metal anchor plate/damper for masonry chimney

Brick Refractory Installation Manual

Stratford II Wood Fireplace Assembly

Depth: 12"

Mr. Heater MH200CVX 200,000 BTU Propane Convection Heater w27.125 Mason-Lite offers several damper options:Overview Big heat right out of the box. The Mr. Heater 200,000 BTU Liquid Propane Convection heater packs a big punch in a small package. The MH200CVX utilizes the natural act of warm air rising to quickly heat up to 5,000 square feet. Equipped with a thermo electric safety valve to shut the gas flow off if the flame ever goes out. Just hook up the supplied 10ft propane hose and regulator assembly to a 20lb propane tank, then easily light the heater