Non-Toxic and Eco-Friendly: Made of quality resin and plastic, durable, non-toxic and pollution-free, harmless to your fish, absolutely safe for the fish you love. Chest sink to the bottom, the ‘chains’ divers attached to the chest hanging in the water, with oxygenation, divers in the water floating swing, like the chest should strive to explore the way; When the diver floats the treasure chest will open and close to reveal the treasure inside, more vivid and active Real underwater movement directions: the air pipe with decorations on valve adjustment or pump connections. Put in the aquarium decorations and fixed position. Adjust the air pressure to make decorations to get your ideal motion effects. Requires an air pump (not included) and 3/16" tubing (not included). Then you can adjust the frequency in which the lid opens. Ideal for various aquariums and tanks. strong for fresh and salt water, your freshwater fish or saltwater fish can play with their new toy Box dimensions: 5.5cm x