Automatic Air ControlLonger, more even temperatures — Automatically regulates the amount of air coming into the firebox for long-lasting, hassle-free heat.Large Viewing AreaEnjoy the flames from almost anywhere in the room — The fire viewing area is 60% larger than other models in the same class.Easy InstallationHassle free — Rear wheels make it easy to slide the Merrimack insert right into place for quick installation.Cast Iron ConstructionSuperior craftsmanship — The firebox, front and door are all made from cast iron with the quality you expect from Vermont Castings.Clean BurningEco-friendly performance — EPA certified emissions of only 3.6 g/hr make this insert one of the cleanest wood burning models available.