Abstract: A shelf unit includes top and bottom, spaced, generally parallel and coextensive horizontal surfaces comprising a plurality of spaced, generally parallel and coextensive elongated horizontal members and a plurality of spaced, generally parallel and coextensive crossmembers extending generally perpendicularly to the elongated horizontal members. Left and right spaced, generally parallel and coextensive elongated vertical side walls comprise a plurality of spaced, generally parallel and coextensive vertical bars and a plurality of spaced, generally parallel and coextensive crossbars extending generally perpendicularly to the elongated vertical members. The upper and lower edges of the left and right side walls are secured to the outer edges of the top and bottom surfaces so that the left and right walls extend generally perpendicularly to the bottom and top surfaces to define a chamber.