368-997 Mitutoyo Holtest II Internal Micrometer Set, 2.0" - 4.0"Mitutoyo Holtest II Internal Micrometer Set These Holtests are versatile, self centering three point internal micrometers for the accurate and efficient direct measurement of internal diameters. Three anvils, evenly spaced at 120 apart, contact the internal wall surfaces and find true alignment with the axis of the bore for accurate ID measurement. Specifications Include 2. 0" 4. 0" Measuring Range 0. 0002" Graduations +0. 00015" Accuracy Set includes