HFS (R) 0-6"x0.0001" ; 6pcs Premium Outside Micrometer Set Solid Metal Frame Carbide Tip (Wood Case) Baked enamel finished frame Micro-lapped carbide tipped measuring face gives mirror finish on the measuring faces to make more accurate reading Clear graduation on satin chrome finish on spindle sleeve to increase readability Advanced spindle design in hardened and precision ground lead screw threads give reliable and accurate reading Ratchet stop allows uniform pressure of spindle to the contact and enhance measurement repeatability