Uns special blackboard that suppresses the use of paper, pencil and eraser (Machine-translation by Google Translate, not legally binding)

摘要

A SPECIAL SLATE THAT SUPPRESSES THE USE OF PAPER, LAPICERO AND RUBBER ERASE, characterized by being provided with a cardboard in black, of any shape and size, one of its faces being covered with a special varnish, based on wax and paraffin, and with a semicircular notch in its lower part. (Machine-translation by Google Translate, not legally binding)