Calculator corresponding to the Costilla fire control system, manufactured around 1940, following the project devised by Colonel Juan Costilla, who died a few years earlier. It is an electromechanical type calculator that receives from a rangefinder or radar, the orientation and distance data to the target, calculates the future point and continuously determines the aiming data to said future point, where the projectiles will meet the target. Because the industrial situation in Spain at the time of its manufacture did not allow to have fully automated electronic systems, the calculator needs the participation of several servants to validate the data received from abroad and transfer the data from the future point to the specialized circuit for calculating the aim of the pieces. For this reason, there are a series of cranks on the outside that move needles in the various indicator clocks on the top. With the fire control system devised by Colonel Juan Costilla, the precision of the shore batteries was greatly improved. NOTE: The side plates have been replaced by transparent panels to better appreciate the electromechanical part of the calculator.