“Caravaggio” flap folders are made from Duralong Special conservation board. They are produced in one piece with two large flaps, two small flaps and four inner tabs, two of them with a clam self-locking design (see the picture detail). They are designed to be completely closed and then to protect the contents from dust. They are equipped with a practical herringbone cotton tying tape, not glued, to be inserted through a slot.