The Starrett 780XT Series Electronic Internal Micrometer provides IP65 level of protection against coolant, water, dirt and dust in hostile shop environments. In addition, it offers extended travel, reducing the need to exchange anvils. The ground contact points seat the internal micrometer faster and more accurately than the spherical contacts found on other gages. The rugged and accurate internal micrometer is available individually or in sets from .040" (1mm) to 12" (300mm). 5/16-3/8" (8-10mm) Range, 3-Point Carbide Contact (300mm).