Set Of 4Diameters: 3/32", 7/64", 1/8" And 9/64"For Use With #6, #8, #10 And #12 ScrewsShank: 1/4" HexUse To Drill A Pilot Hole And Countersink In One StepFor Use In Wood And PlasticsReplaceable Pilot Bits Are Securely Held By A Set Screw And Can Be Adjusted For Different Screw Lengths