Upgrade 7 Blades: This PLATATO upgraded version of the duct crimper features a more efficient 7-blade design for faster crimping of sheet metal ducts. Suitable for 24-28 gauge sheet metal for duct work, such as HVAC, gutter downspout, stove pipe, dryer exhaust vents, chimney pipe, etc. Easy to Use and Efficient: Our 7-blade gutter crimping tool allows to efficiently create uniform crimps for the end of duct pipe. The 10.5-inch length provides enough leverage and 1.89" throat allows for sufficient crimping length, making rain gutters and downspout installation much easier. Convenient Design: The newly designed duct crimper tool comes with a security lock to ensure safety use and keep the sheet metal tool compact for easy storage. It also has a lanyard hole design, which is convenient for working at altitude. Heavy Duty and Well Made: The blades of this sheet metal crimping tool are made of 50# steel plate that has high hardness, and the surface is treated by bright plating fin