A rare architect's tool / device which was used to draw. With the aid of a clamp it can be mounted on the drawing board. Made of steel and the rulers are plastic Thanks to the springs it is easy to move and adjust and you can set the angle using the large rotary knob. The spring strength can be adjusted by choosing different holes. Size is ca. 50 cm when folded up The rulers are attached by two bolts on each ruler. One ruler is 20 cm and the other is 30 cm. There is another number on it (MZ0213), I think it is a serial number. There is also a case and a key, look at the photos to get a better idea of this item. Small crack in the side of the case!