Maker's Name: 
Standard Gage Co Inc
Where made: 
17 × 19 × 27.5 cm

The dial gauge is mounted with the probe vertical, above a heavy sliding plate with an optically flat surface. The object to be tested is wrung on to the plate with a thin smear of oil. As the plate slides the gauge indicates the relative change in the height of the surface to one ten-thousandth of an inch. The sliding plate may be rotated to allow surface testing in other directions.