ICON SYMBOL FILE NAME TYPE SUBCLASS Concentric.sym Concentric diameter change In-Line Fittings Damper.sym Damper Valve Duct Check Valve.sym Duct Check Valve Valve Duct to Duct Penetration.sym Duct-Duct Penetration In-Line Specialty Component Duct to Pipe Penetration.sym Duct-Pipe Penetration In-Line Specialty Component Eccentric.sym Eccentric diameter change In-Line Fittings Filter.sym Filter In-Line Specialty Component Vent.sym Vent In-Line Specialty Component