It's a ruler made from pieces of beads, where the grooves represent 1 mm  to estimate the size of small objects. 1 bead measures 10mm and the number represents the magnitude of the measurement. NOTE: Tolerances aren't checked yet, and can be applied in the fabricator's chosen slicing software. English unit versions will be updated. Fairly easy to CAD so feel free to remix. STL and STP files are available.  Other file types can be made available so feel free to comment