The radio latino is one of the most significant military instruments of the Renaissance. When stored in its case it resembles a dagger in shape and size. The handle conceals a magnetic compass, while the blade is composed of small hinged rods engraved with various measurement scales. The device served to measure the height of ramparts, to map fortresses, and to measure calibers, projectile weight, and cannon elevation. To measure the height of a rampart, the user sighted the top of the structure with the instrument from two points lying on a perpendicular to the rampart itself. The values displayed by the plumb line on the shadow scale at the two sighting points made it possible to define a triangle of known dimensions. This triangle resembled the one whose base was the known distance between the two sighting points and whose height was the top of the rampart. By comparing the triangle of known dimensions with the other, similar triangle, the user could determine the height of the rampart.