C.A. Ferrero-Savona Model FER H-39 concrete calculator (Ver 3) Made in Savona, Italy. Based on the original design by Washington Sabatini (1923-1966). Presents original case in bad conditions. The straight edge constitutes the quadrant formed by eight sliders ring, each representing a variable of calculation formulas, and by an outer ring fixed, showing a scale of weight values in kilograms. On each slide are marked with the indices of the possible values of variable. The crank handle as slides through eight buttons placed along the arm. Raising a button, the corresponding ring remains stationary. It was also produced directly by W. Sabatini. Third model (Fer H-39) is shown in this image. Basically it is a compact restyling of second model and it was produced by Ferrero brothers, who acquired Sabatini patents. The original Sabatini device is in the Milano Science Museum. Properly packed, track and trace shipping.