Vintage proportional divider from PREMA, n.p. Bytča (Czechoslovakia). First you have to release the bigger screw. Than you can start to move with the smaller screw (via rail) on the scale up and down to the scale mark of your choice. Than you need to tighten the bigger screw and you can start to work. One side will be sample of original distance, the opposite side will be the chosen proportion. There are two scale marks: 1st is for the lines (přímky) and the second for the circles (kruhy). Item is used, but still in nice condition and fully functional. Together with the divider you will also receive an used original storage cardboard box. Year of production: 1956.