Designed for aggressive cutting through medium-thickness metals， this high-durability 4 in. 18 TPI METALWOLF WAVE EDGE Bi-Metal Reciprocating Saw Blade delivers strength you can count on for challenging projects. With up to 50% longer life， it’s engineered to maintain cut consistency with revolutionary WAVE EDGE technology. High-speed cutting is made possible by its sharp， steel cutting edge while the spring steel backing firms up the blade and helps reduce breaks.