Mitutoyo Tubular Inside Micrometer Set This set allows you to measure a wide range of ID measurements by combining extension rods (pipes) and anvils with the micrometer head. Carbide-tipped measuring faces are available. Specifications include... 2" - 40" Measuring Range 0.001" Grads Accuracy: +{.00012+.00005n+(.00004xR/2)} R=Maximum Measuring length (inch) n=Number of Rods Fraction rounded up Set includes... Micrometer Head Extension Rods .5", 1", 2" (2 pcs), 4", 8" (2 pcs), 12"