mountable and demountable stackable container having vertical plastic walls and stiff flat bottom , for complementing closets , cupboards , bookshelves , selves , pieces of furniture , storage areas , and other office areas or even directly on the floor , comprising two flat plastic modules having folds as hinges to form a container , the ends of said modules being secured by clamp elements and a stiff flat bottom base , made of wood , for example , that is accommodated in the guide groove located in the plastic modules and that can be secured to said base through tab projections having injected lugs .