Micro 100 THMA-616 Boring & Grooving Bar Holders; Inside Diameter (Inch): 1/4 ; Inside Diameter (Decimal Inch): 0.2500 ; Outside Diameter (mm): 16.0000 ; Overall Length (mm): 69.8500 ; Overall Length (Decimal Inch): 2.7500 ; Overall Length (Inch): 2-