Aggressive feed-screw design which allows the bit to pull through the wood faster and without effort, resulting in fast drilling. The SWITCHBLADE replaceable blade system ensures the blade is always razor sharp. Productivity, and bit life, is increased by eliminating resharpening downtime. Suitable for all general contractors, electricians, plumbers and HVAC engineers who require to drill through holes in wood for all types of pipe, vents and wire trunking. Each self-feed bit comes with a replacement blade, feed screw and set screw. Includes QUIK-LOK extension. Supplied with allen key. Suitable for Soft & Hard Wood 35-65mm Dia. Drill Bits Steel Self-Feeding Threaded Tip Fits 13mm Chucks Replaceable Blade System Feed-Screw Design High Productivity Suitable for Soft & Hard Wood 35-65mm Dia. Drill Bits Steel Self-Feeding Threaded Tip Fits 13mm Chucks Replaceable Blade System Feed-Screw Design High Productivity