VentAir Systemss offers Mild Steel Flanges for Ducts. VentAir Systemss offers air conditioning duct, pre fabricated duct, air conditioning duct, ventilation duct, exhaust duct and duct accessories. The Mild Steel Flanges for Ducts are made from MS Angle of reputed makes. The holes are provided at specified interval on one face of angle for jointing it to another flange and on the other face to rivet it to the duct piece. The Mild Steel Flanges for Ducts are provided in pairs in order to ensure proper hole matching of the mating flanges. These products are used in a wide range of industrial and commercial applications.