The Irwin Marathon 6 1/2in. 18-tooth circular saw blade is designed tough and long lasting for the professional. The thin kerf design provides faster, cleaner cutting action as less material is being removed. The hardened plate runs truer and avoids warping. C3 carbide tips provide long life and are impact resistant. The specifically engineered heat vents reduce heat and resin build up which can lead to blade binding and warping. Marathon's unique shoulder design puts more support behind each tooth and provides for consistent chip removal. Marathon saw blades are truly ""Long Distance Runners.""