Boiler/Furnace Brush; Type Flat, Single Spiral/Single Stem; Brush Size 1/2 Inch x 1 Inch x 4-1/2 Inch; Overall Length 48 Inch; Bristle Size 0.008 Inch Diameter; Bristle Material Spring Grade Tempered Wire; Application HVAC/Refrigeration/Boiler/Furnace/Heat Exchanger/Heater/Radiator