A mixing system typically for use in a container for mixing its contents, the mixing system including a cap unit, an extension unit and a magnetic mixing unit that is attached to the cap unit by the extension unit. The magnetic mixing unit can be folded to permit insertion and/or removal of the system via a mouth of the container. The extension unit and magnetic mixing unit connect via a hinge formed by upper and lower hinge portions that meet at a pivot point. The hinge portions extend from the pivot point along a first axis. The magnetic mixing unit includes a first magnetic elongate member that extends from the lower hinge portion along a second axis that is substantially perpendicular to the first axis, and a second magnetic elongate member that extends from the lower hinge portion along the second axis in the opposite direction relative to the first elongate member. The magnetic member(s) may be provided by a plastic coated magnetic stir bar.