5 Blade Sheet Metal Tool: the 10.5in sheet metal crimper is made from precision forged alloy steel applied for crimping heavy or thin metal sheet 22-28 gauge galvanized or stainless steel ductwork; Produces factory precision indentations in stove pipe and round duct with just a squeeze; The maximum cutting force of duct crimping tool is 0.16 inch/ 4 mm Downspout Crimping Tool: the head of the sheet metal tools is made of A3 sheet (carbon structural material with high hardness and yield strength 235MPa) and the handle is made of 45# steel plate (medium carbon structural steel with high hardness and yield strength 355MPa) which allowing it to withstand tough working conditions Duct Knife HVAC Convenient Design: TPR material handle of our hvac hand tools with non slip grip for comfort and ease of control, and the gutter tools metal downspout crimper includes an integrated lanyard tether hole for working at heights; Spring loaded lever mechanism reduces over exertion and hand crampi