Features and Benefits:�Easy size reference: Bit and blades are engraved for quick and easy size identification�Longer bit life: Replaceable blades are made of hardened steelGet the replacement blade that makes your Milwaukee 2-1/4 in. SwitchBlade Selfeed bit instantly new. Milwaukee SwitchBlade replacement blades are made of hardened steel for long life. They're easy to change out, so you�re always ready for faster drilling and less downtime on the job.