Curta Mechanical Calculators (Type 2) were the golden standard for calculation until the 1970's when they were displaced by electronic calculators. The user would input a value using the sliders and then add (or subtract by lifting the crank) it to the output value. By turning the crank you then performed the operation. You could also scale your input by a multiplier determined by the rotation of the carriage. The output value (and the crank counter) were cleared by lifting the carriage and spinning the top component.
All 4 formats [c4d, max, obj, fbx] come with all textures included. Cinema 4d version comes in R16 format and textures automatically load. 3DS MAX comes in 2015 format and textures automatically load.
The shown previews were rendered with both PHYSICAL RENDERER and STANDARD RENDERER (for the turntable). The scene is lit with a physical sky and global illumination, ambient occlusion, and depth of field were used.
The scene comes with the model material, 10 numerical materials (0-9) and 2 scene materials (the blue background essentially).
Main textures [diffuse, specular, glossiness, normal, and bump] are all 2048x2048.