Very high quality and made in Japan these are one of those things you wish you'd had years ago. Its a vernier scale on a ruler! Very handy for workshop measuring and marking in both woodworking and metal workshops.
3 sizes available:
One can use these tools for laying out guitar frets, marking off lengths to be cut, setting up a stop on a saw, for scribing hole centers from an edge perhaps or for taking a measurement.
Easily read a measurement down to 0.1mm with the scale stopper.
There is an excellent metric/inch conversion chart on the back of these rulers.
For information on how to read a vernier scale we suggest checking wikipedia or similar, there are many excellent explanations out there.