Starrett, 73722, Mechanical Micrometer Heads; Minimum Measurement (Decimal Inch): 0; Maximum Measurement (mm): 1.00; Maximum Measurement (Inch): 1; Thimble Dia (Decimal Inch): 0.7500; Thimble Dia (mm): 18.00; Digital Counter: No; Graduation (Decimal Inch): 0.0001; Spindle Type: Flat; Rotating Spindle: Yes