Precision measurements to the thousandth and ten-thousandth of an inch require a quality micrometer. Central Tools manufactures many types of micrometers in inch and metric to meet all your measuring needs. Extra Hard Measuring Surfaces - Anvil and one-piece spindle are made of finest quality tool steel. Careful lapping on our own special machinery assures that faces are square and parallel. Simplified Zero Adjustment - Lets you reset your Central micrometer simply with the hex key provided. Friction Stop - Provides uniform pressure under all measuring conditions. I-Beam Frame - Designed to maintain dimensional stability. Powder-coated. Easy Reading Graduations - Machine spaced. All thousandths graduations are numbered so you can read directly without counting. Carbide Faces - On models with .0001 " graduations. Spindle Lock - Holds spindle securely for transferring measurements. Meets Federal Specs - GGG-C-105C on models with .0001 " graduations. Standards Included - On all micrometers above 1 " or 25mm. Range: 3-4" Grad: .001"