Standard Abrasives Unitized Wheel Steel Screw Mandrel 850034, 7/8 in x 1/4 in Shank, 1 per case The Standard Abrasives Unitized Mandrel secures a 2-3? Standard Abrasives Unitized Wheel to a rotary tool for edge deburring and finishing applicationsThe silver button fits wheels with thicknesses of 1/8? or 1/4? and the black button accommodates wheels with thicknesses of 3/8? and 1/2?Use this mandrel with a Standard Abrasives 913 or 933 Unitized Wheel (sold separately). Product Information Brand 3M Part # 7000121879 Origin Country USA Product Type Mandrels Product Information1/4? shank fits unitized wheel with 3/8? center holeAttaches easily to die grinder or rotary toolDesigned specifically for use with 2-3? Standard Abrasives 913 and 933 Unitized WheelsMade of steel for enhanced durability, longevity and toughnessMaxRPM 25,100Versatile mandrel comes with caps that accommodate wheel thicknesses from 1/8? to 1/2?