Micro 100 TD1-MR11-3-866 Boring & Grooving Bar Holders; Inside Diameter (Inch): 3/16 ; Inside Diameter (Decimal Inch): 0.1875 ; Outside Diameter (Decimal Inch - 4 Decimals): 0.8661 ; Overall Length (Decimal Inch): 3.2000 ; Head Diameter (Decimal Inch