SPI Hole Mike 3-Point Internal Micrometer Set Specifications Include... 2.00" - 4.00" Measuring Range 0.0002" Readings 3.54" Measuring Depth Includes 3 Setting Rings Includes Certificates of Calibration Includes 6" Depth Extension Features include... Three point internal micrometer for precise, direct measurement of bore diameters. Self aligning and self centering Carbide measuring anvils Suitable to measure to within .050" of bottom of blind hole, up to 4" capacity Feelers taper toward the back for positive reading of the front edge Ratchet stop provides uniform measuring pressure
