PRECISE MEASUREMENT INSTRUMENTS AND APPARATUS, NAMELY, MICROMETERS; CALIPERS; GAUGES USED FOR MEASURING HEIGHTS AND DEPTHS; GAUGES USED FOR MEASURING DIAMETERS AND SIZES OF WORKPIECES; DIAL INDICATORS; COMPARATORS USED TO MEASURE DIAMETERS OR SIZES OF WORKPIECES; PROTRACTORS; SLOPE INDICATORS; AND BENCHES FOR MOUNTING SUCH WORKPIECES AND INSTRUMENTS SOLD AS A UNIT THEREWITH