ALL-IN-ONE KIT: Features two spinlock universal arbors, steel pilot bit and six hole saws with progressor tooth design SPINLOCK UNIVERSAL ARBOR: Fits all brands and sizes to simplify diameter changes with fast plug removal and tool-free install THE PILOT BIT: Designed to start holes in a variety of materials PROGRESSOR TOOTH DESIGN: Hole saws feature alternating teeth size for performance, cutting faster and lasting longer in wood, metal and plastic materials DURABLE HOLE SAW MATERIAL: Hole saws are made with 8% cobalt alloy REINFORCED SHOULDERS: Provide added strength and longer life to the hole saws PLASTIC CASE: Organizes and protects kit