Old style round hole
Fein 6-35-02-096-02-3 Fein Blades for cutting sheet metal, fiberglass, or wood. 2-1/2 in. Diameter Single Blade. These saw blades are designed to cut harder material and last longer. Smaller size can cut in tight spots where other blades can't.
CA Prop 65 WARNING: Drilling, sawing, sanding or machining wood products can expose you to wood dust, a substance know to the State of California to cause cancer. Avoid inhaling wood dust or use dust mask or other safeguards for personal protection