General Tools & Instruments 132ME 3-Inch English and Metric Pocket Sliding Bar Caliper
This pocket caliper makes quick accurate inside, outside and diameter measurements.  This caliper is made in stainless steel with slide caliper with inside and outside readings in metric and inches.  Decimal equivalents.  3" capacity.  Graduations in 32nds and mm.  Inexpensive but of rugged construction.