Sliding Caliper

The Vernier scale allows for a reading accuracy of 0.1 mm, by indicating exactly where a measurement lies in between two marks on the main scale.

The Sliding caliper is made entirely of metal, and the main scale is engraved in millimeter intervals from 0 to 150 millimeters.  The Vernier scale is engraved in 2 mm intervals, from 0 to 20 mm.