fish tank bubbler. [Decoration] Calabash shaped bubble stone design, unique and fashionable, perfect for decorating any fish tank. [High Quality Material] Air Stones are made of high quality ore material, environmentally friendly, and stable.gifts for rich peoplechristmas gifts fish tank bubbler.[Size] Fitment: 4mm Standard Interface. Diameter: Approx. 2cm/0.79in. pawfly air stone. [Easy to use] Bubble air stone is easy to use, simply connect airline and air pump to the bubble stone, and place in the aquarium. 5 x air stone ball black. [Application] Help to dissolve more oxygen, increasing the amount of oxygen in the water. Ideal for creating many oxygenating bubbles within your aquarium.