SPI Deep Throat Micrometer Great for use with sheet metal and similar applications. Features Include... 0-1" Measuring Range 0.001" Graduations 0.0002" Accuracy 12" Deep Throat 0.250" Spindle Diameter Clear graduations on satin chrome finish Enamel finish frame. Ratchet stop and spindle lock Carbide tipped measuring faces Includes Certificate of Calibration Furnished in fitted case.