The Bosch General-Purpose Professional Bi-Metal Hole Saw set is an easy-carry all-in-one kit, which contains 11 different hole saw sizes that help you tackle most common applications. Bosch Bi-Metal M42 Hole Saws with Triangle Chip-Clearance Slot 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 long life. The triangle chip-clearance 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 takes a bite out of multiple materials – such as wood, metal or drywall.