Letter-envelope model (Machine-translation by Google Translate, not legally binding)

摘要

New letter-envelope model, characterized by being constituted by a rectangular sheet prolonged by one of its short sides in respective flaps whose border lines with the sheet are raised, and endowed with a transparent window located transversely in one of the two upper rooms of the four in which the leaf can be ideally divided by two middle lines, one longitudinal and one transversal. (Machine-translation by Google Translate, not legally binding)