Mitutoyo Series 368 Holtest

Three-Point/Two-Point Internal Micrometers

These Holtests are versatile, self-centering three-point internal micrometers for the accurate and efficient direct-measurement of internal diameters. Three anvils, evenly spaced at 120° apart, contact the internal wall surfaces and find true alignment with the axis of the bore for accurate ID measurement.


  • TiN-coated measuring contact points (over 6mm / .275” range models) provide excellent durability and impact resistance and allow the instrument to measure to the bottom of a blind hole (up to 100mm / 4”models).
  • Highly durable because of carbide-tipped contact points (anvils up to 12mm / .5”models).
  • Measure deep holes using an extension rod (optional) which is available on models over 6mm (.275″) measuring range.
  • With Ratchet Stop for constant force.
  • Setting rings for zero point adjustment are optional.
  • Supplied in fitted plastic case up to 100mm / 4”. Over 100mm / 4” supplied in wooden case.
SKU: TMI-118 Categories: ,