Fowler 52-250-024 EZ-Read Disc Digit Micrometer, 3-4" Measuring Range, 0.0001" Graduation Interval, 0.0002" Accuracy Outside micrometer with choice of measuring range and disc-style anvil/spindle pair measures thickness of narrow grooves and difficult or closely spaced areas, such as slots and recesses Digit display has 0.0001" graduation intervals and 0.0002" accuracy for precise readings and accurate measurements Hardened, ground, and micro-lapped anvil/spindle pair provides wear resistance Locking lever locks measurement in place for accurate reading Friction thimble provides smooth and quiet operation, and is suitable for one-handed operation