Suburban's Dynatrail are prime examples of how powerful a compact ducted furnace can be. Energy saving solid state electronic ignition. Low amp draw demands less from your battery. Gasket-sealed vent assemblies, steel gas manifolds, sealed forced-draft combustion, chrome-plated vent cap and wall thermostats are standard equipment on these Suburban Dynatrail furnaces. Duct Outlet Size: Sides 4" round, Bottom 10" x 3-1/4".