With a new and improved design, these 7-1/4" x 24 Tooth Portable Corded Circular Saw Blades from Irwin (24030-20PK) feature a new heat vent / expansion slot design that reduces vibration for longer life and straighter cuts. The fully hardened plate runs truer and longer than standard circular saw blades. Every other tooth is thinner for faster cuts, plus the construction grade carbide teeth provide longer life.