String modular bookcase by Kajsa & Nils "Nisse" Strinning for String Design AB, made in Sweden in the 1950s. A system made from 1949, this example is from the 1950s although two-three elements are earlier. All modules can be freely arranged.
It consists of fifteen shelves (three wide, twelve thinner), eleven grid side elements, one module with wooden sliding doors, one with glass sliding doors and one with flap and inner compartments.
Modules equipped with working key and lock.
They show some traces of time, for example, an abrasion of one of the black metal grid elements.