Non intrusive agitation system

A first inter-related product for non intrusive agitation of a fluid, suitable for cell culture, provided in the form of a device comprising:

• a container to contain directly or by a further second container the fluid, the container comprising an inner part, an outer part and walls, at least one of the walls comprising a first flexible element having an internal surface oriented towards the inner part of the container and an external surface oriented towards the outer part of the container,
• main movable stirring means located inside the container to stir at least the fluid,
• wherein,
• the external surface of the first flexible element is to interfere mechanically with an external movable impulsion means thus creating a deformation on the internal surface of the first flexible element such that said deformation of the internal surface of the first flexible element has a mechanical interference with the main movable stirring means, and movement of such impulsion means is transmitted to the main movable stirring means by interposition of the first flexible element,
• wherein the main movable stirring means comprises first protrusions, and at least one of the first protrusions are cylindrical protrusions, semicylindrical protrusions, semispherical protrusions, idle cylinders, idle spherical elements, retractile bars, or a combination thereof.