Micro 100 Boring Bar, manufacturer part number QHBBC-2101000-004.
Specifications: Minimum Bore Diameter: 0.2100 in; Maximum Bore Depth: 1.0000 in; Shank Diameter: 1/4 in (0.2500 in); Overall Length: 2-1/2 in (2.5000 in); Hand Direction: Right; Neck Diameter: 0.1850 in; Centerline Offset: 0.1050 in; Face Dimension: 1/8 in (0.1250 in); Head Width: 0.1975 in; Length from Holder: 1.3530 in; Corner Radius: 0.0040 in.
Coating/Finish: Uncoated. Unit of measure: Inch.