Silicone coat allows the blade to slice easier through material reducing pitch and resin buildup when cutting pressure-treated lumber. Construction-grade carbide teeth deliver longer blade life. Every other tooth is thinner for faster cuts. The innovative heat vent/expansion slot design reduces vibration for longer life and straighter cuts. Plate is fully hardened to run truer, longer. 120 tooth count with optimized, symmetric 60-degree tooth design is ideal for cuts to gutters, vinyl siding and PVC piping. IRWIN Tools MARATHON Vinyl Siding Circular Saw Blade, 7 1/4-inch, 120T (21830ZR)