Aggressive feed screw allows the bit to pull through the wood faster. Each bit comes standard with a second replacement blade made with hardened steel; size and model number engraved on each bit. Used by plumbers, HVAC contractors, electricians in applications such as drilling holes in all types of wood for pipe, vents, gas lines and bulk wire routing. Includes: 2-9/16" switchblade self-feed bit, (2) replaceable blades, (2) feed screws, (2) set screws, one (1) hex wrench.