An outer case has a lower portion with front, rear and side faces. The side faces couple the front and rear faces. The lower portion terminates in an open lower end and an upper end. The outer case has an upper portion terminating in a closed upper end. The outer case has a lower end. An inner case has front, rear, and side faces. The side faces couple the front and rear faces. The upper portion terminates in an open upper end and a lower end. The inner case has a lower portion terminating in a closed lower end and an upper end. A pair of parallel slots is formed in the rear face of the inner case. The slots are at a central elevational extent of the rear face of the inner case.