The most common fiberglass duct board tools are the Red and Blue tools. The Red Tool is a V-Groove tool which carve out a V shape in the fiberglass duct board. By carving out a V, the board can then be folded into a 90º Bend. If you carve out three V's then you can form the four sided square or rectangular duct.
The Blue Tool is a 4 in 1 End Cut off tool which is used to finish the edge of the piece of fiberglass duct board. The Blue Tool is also referred to as the "staple flap" tool. The blades on the Blue Tool can be swapped out to form four seperate types of end cut offs.