Penn Plax® Action Air® Aquarium Ornaments bring animation and charm to your underwater world while aerating your tank. This Action Air® Barrel of Jewels gives your aquarium that sunken treasure look & feel. The action of the barrel half opening & closing reveals the interior treasure while bubbles escape through the open barrel providing your tank with much needed air. A ship"s wheel and pirate"s skull add to the decor. Every Action Air® ornament is created with great detail and weighted to help them stay put. Simply connect the ornament to a standard 3/16" airline from your air pump (not included) and watch the treasure chest gently open & close as a steady stream of bubbles rise from the barrel helping to aerate your tank. Use your pressure control valve (not included) to adjust the motion and the volume of air. Each ornament is made from a durable plastic resin that is safe for your aquarium. Fun to watch and entertaining for you & your fish, Action Air® ornaments fit in almost any tank and come in a variety of styles & sizes so you can continue to add to your aquarium design. Barrel of Jewels measures approximately 3-1/2"x 2-1/2"x 3" high when open.