Dasqua 2-4" 0.001" inside tube micrometer. Resolution is 0.001". Extension rods included are 0.5" and 1". Accuracy is 0.00025". Strictly made in accordance with DIN863. Hard chrome plated. No-glare satin finish. Included extension rods provide a wide measuring range. Supplied with a standard gage for zero setting. Measuring rods hardened, ground and lapped. Includes one standard micrometer head from 50-63mm and various extensions. One or more extensions can be screwed into the standard micrometer head depending on the desired measuring range.