Suitable for: tank, aquarium. Shape: rod. Material: mineral, plastic. Outlet connection diameter: 5 mm (max. stone length: 15 cm. Overall dimensions: approx. 16.5 x 2 x 1.3 cm. Color: green and blue. Product description Suitable for freshwater and saltwater aquariums and hydroponics. Commonly used to increase the dissolved oxygen content in the aquarium. Air stones allow the aquarium enthusiast to create beautiful bubble walls that not only look good, but also contribute to aeration and circulation of the water. Contents: 4 air stones for aquariums.