Non-toxic and eco-friendly materialsMade from quality resin and plastic, durable, non-toxic and pollution-free, safe for your fish; Absolutely safe for the fish you love. Great-looking ornament and really fun to watch when put together. Real underwater movement directions: the air hose with decorations on the valve adjustment or connections of the pump. 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. Chest sink at bottom, plungers of the "chains" attached to the chest suspended in the water, with oxygen, 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 Ideal for various aquariums and safe for fresh and salt water, your freshwater fish or fish saltwater can play with their new toy Scope of delivery: Aquarium decoration*1 Warm tip: Dear buyer, due to lighting effect, monitor's brightness, manual measurement etc, there may be some slight differences in the color and size between the photo and the actual product. Sincerely hope you can understand Thank you