6 Piece A-F High Speed Steel Adjustable Blade Reamer Set ~ Each reamer expands to the next size. ~ Ends are center drilled so blades can be sharpened in place. ~ Blades are adjusted by loosening one nut and tightening the other. ~ Adjustable blade lets you handle multiple hole sizes with a single tool and multiple tools in each set let you handle even more hole sizes, making these sets virtually indispensable. ~ Square end allows the user to turn the reamer by hand with an adjustable wrench or straight handle tap wrench. ~ Reamers are hardened, precision-ground high speed steel with a black oxide finish and include a wooden storage box.