Dundas Janine Worm Gear Clamp, Heavy Duty, Suitable For Use With: Semi-rigid Or Rigid Aluminum Ducts, 4 in Diameter, Steel, Galvanized, For Fastening Ducts To Aluminum Pipes Or Elbows. This item is Dundas Janine MC4ZW Metal Clamps . Used for Lighting & Fans, Lamps. The Product is manufactured in China.