Glowing columns of light produced by the clear acrylic columns create an internal shaft of light filled with color and an endless stream of bubbles. The two largest Water Columns™ are octagonal designs (15" or 18" in diameter) and incorporate top and bottom lighting. AquaLume designs are 3" or 6" diameter columns and conceal all internal components within its black acrylic stability base (including air pump, light fixture and interchangeable color filters). AquaLumes and Water Columns reach 5 to 7 feet tall. 5 circular Aquashelves™ are available for highlighting your favorite treasures. LS-5RS and LS-6RS include adjustable 12 inch diameter shelves where GT-61RS includes 14-1/2 inch diameter shelves.