Igaging® tri-point internal bore gauge / micrometer set features ul style 'margin-top 0px; padding-top 5px; padding-bottom 5px;' range 3.5-4.0"/87-100mm tolerance 0.00025" ip54 protective rating moisture and dust resistance x-large lcd display inch/metric conversion resolution 0.00005"/0.001 mm contact points are designed to allow measurements near the bottom of blind holes carbide measuring surfaces friction thimble spc/usb data output 6" extesion rods available. Setting ring and wrench included battery 3v cr2032 included supplied in aluminum carry/protective case