Fowler Full Warranty Inch Digit Outside Micrometer, 52-224-004-0, 3-4" Measuring Range, 0.0001" Graduation Full 1 year warranty offered by Fowler High Precision, an American company Outside micrometer with choice of measuring range, and flat anvil/spindle pair with 0.256" diameter measuring face for general purpose measuring Digit display has 0.001" graduations and vernier scale to 0.0001" and an accuracy of 0.0002" for precise readings Hardened and precision-ground anvil and spindle have micro-lapped carbide measuring faces with 0.00012" parallelism on 3-4" micrometers and 0.00003" flatness for accurate measurements Hardened, ground and lapped spindle thread provides smooth movement, accuracy, and long life, ratchet stop applies constant force for repeatability between users