Steel Rule Rustless - Rigid - Precision.
Metric/English.
Marked two sides, four edges.
Graduated, inches, 16ths, 32nds, 64ths, 10ths, 20ths, 50ths, 100ths.
Mm. 1/2mm figured every 10mm in mm.

Length. 150mm
Width 19mm
Thickness 0.45mm