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... 8-40" Measuring Range 0.0001" / 0.001mm Resolution Accuracy: + (.00015+.00005n+.00005R/2) R=Maximum Measuring length n=Number of Rods Fraction rounded up Set includes... Digital Micrometer Head Extension Rods 1", 2", 4" (2pcs), 8" & 12"