Check the listing for details. Angle Flange (Angle Ring) - Industrial Grade - 4" dia.. Condition: New. Listed at 40.99 USD. Connecting Flanges for Ductwork Systems Industrial grade anfle flange (angle ring)Used for connecting sheet metal parts togetherUnpaintedOther finishes available from mfg: Galvanized, aluminum, stainlessListing is for (1) un-painted mild steel angle ring Item Weight.85 poundsOriginMade in USAItem model #AF-4Size4 1/16" IDColorun-painted mild steelFinishUnfinishedMaterialironPatternUnpaintedShapeCircular Thickness 10 ga.Item Package Quantity1Number Of Pieces1 Capacity Description 6 bolt holes, bolt hole size 9/32, 4 1/16" ID, 5 5/16" BC, Special FeaturesPaintableUsageConnecting Sheet Metal PartsAssembled Diameter4 inches Technical DetailsPaintableProduct Description Bluefin pressed and rolled steel angle rings are used widely in joining ductwork together in dust and fume control work. All rings are of mild steel, unpainted. All sizes are in stock for immediate shipment. 3" through 5" diameter angle rings are press formed, and above 5"diameter are roll formed and welded. They are available with or without holes. Holes are standard. Nuts and bolts not included. Larger angles, channels, bars and other sizes rolled to order in steel, aluminum, stainless and other alloys. Square and rectangular flanges are also available. All angle rings and flanges are punched on automatic equipment.