T2 technology tooth design delivers up to twice the life and cuts heavy materials more easily. Bi-metal construction allows blades to bend and flex without breaking. Designed to minimize friction and heat build-up while cutting through the widest variety of metal materials. 18 tooth per inch blades are best for use with medium-thickness metals. LENOX Tools Bi-Metal Reciprocating Saw Blade, 8-inch, 18 TPI, 5-Pack (20578818R).