Exchange-a-Blade 2110650 4-1/2-Inch Diameter Multi-Cutting Carbide Blade
Exchange-A-Blade mulit-cutter provides a smooth cutting in multiple materials such as plastic pipe, fiber glass, light aluminum extrusions, mouldings, plywood and particle board.  It fits both 4-1/2" and 5" protable saws, and comes with 5/8" and 7/8" bushings.  It has 40 Tungsten carbide teeth with a zero degree tooth angle for safe cutting.