17-635-4 SPI Micrometer Set 0-6" with CertSPI Standard Outside Mechanical Set Set includes 0 6" Measuring Range 0. 0001" Graduations Accuracy 0 1" Model: + 0. 0001" 1 2" Model: + 0. 0002" 2 3" Model: + 0. 0002" 3 4" Model: + 0. 0002" 4 5" Model: + 0. 0002" 5 6" Model: + 0. 0002" Ratchet Stop Carbide Spindle Faces 0. 25" Spindle Diameter NIST Traceable Calibration Certificate Furnished in fitted case Micrometers included in set 0 1" Outside Micrometer 1 2" Outside Micrometer with standard 2 3"