Micro 100 QSG-187-750 Boring & Grooving Bar Holders; Inside Diameter (Inch): 3/16 ; Inside Diameter (Decimal Inch): 0.1875 ; Overall Length (Decimal Inch): 4.8000 ; Head Diameter (Decimal Inch): 1.0630 ; Series: QSG ; Manufacturer's Part Number: QSG-