Abstract: A lunch box, configured for attachment to a portable container, includes a body having an interior accessible through an opening, a lid movably attached to the body and configured to selectively cover the opening, and a locking mechanism attached to the body and having a first attachment component and a second attachment component. The locking mechanism has (i) a first attached configuration wherein the first attachment component is selectively coupled to the second attachment component such that a portion of the portable container is selectively retained between the locking mechanism and the body, and (ii) a second attached configuration wherein at least one of the first and second attachment components is selectively coupled to a portion of the portable container.