The BYMAX No. 270 Taper Gauge is a very useful tool, especially for bearing work and for gauging slots and many other applications, it fits in your shirt pocket.
The gauge is made of quality tool steel and is accurately tapered throughout its entire length for quick and convenient measure of slot widths, etc.
Specification:
.010-.150″ / 0.3-4 mm
7/16″ (11 mm) wide by 6-1/4″ (160 mm) long
Although a big expensive, this quality tool can be and has been used as a precision shim. One side is graduated from .010 to .150 in thousandths of an inch and the reverse side from 0.3 mm to 4 mm in one-twentieth of a mm (0.05 mm)