Bosch Bi-Metal M42 Hole Saws with a Triangle Slot Design are built with improved durability, clean performance and easier plug removal in multiple materials. The hole saw is manufactured with Bosch's enhanced M42 alloy material, which contains 8% cobalt alloy. It is able to withstand high-temperature applications for clean cuts and deliver 20% more life. The triangle slot design improves efficiency of plug removal and reduces heat. This accessory features the Progressor tooth design for fast, clean holes. With a reinforced shoulder for added strength and longer life and a deeper cup, the hole saw takes a bite out of multiple materials – such as wood, metal or drywall.