An IC socket includes a base, a cover engaged upon the base and moveable along a front-to-back direction relative to the base, and a lever for driving the cover to slide on the base. The secondary portions may be under separate commitment control that is asynchronous to the commitment control for the mandatory portions, or may be under no commitment control at all. The closure lid is configured to be inserted within the open end of the container, and is adapted to engage in a sealing relationship with the outer wall of the container.