Harvey Tool 894524 Diamond-Pattern Router Bits; Cutter Diameter (Inch): 3/8 ; Cutter Diameter (Decimal Inch): 0.3750 ; Shank Diameter (Inch): 3/8 ; Shank Diameter (Decimal Inch): 0.3750 ; Overall Length (Inch): 4 ; Overall Length (Decimal Inch): 4.00