Abstract: A device for controlling a relative humidity level in an enclosed volume storage device includes a plurality of container segments each including two side walls with internal edges joined at an interior edge of the container segment, an outer wall extending between external edges of the two side walls, a base wall extending between bottom edges of each of the two side walls and the outer wall of the container segment, and a permeable top wall. The container segments are configured in a first instance to be compactly adjacently positioned so that each side wall of a container segment abuts another side wall of another container segment and the segments are radially arrayed around a central axis of the device. A binding element is applied to maintain the segments in this position. The binding element is removable to allow the segments to be individually distributed within the storage device.