The Air Stone is designed to gradually diffuse the air into the water tank and provide oxygen for the fish to breathe. If you are a fan of aquatic animals, the surroundings of your house are essential. Our air stones are made of high-class materials and are durable. Features -Color:Blue -Material:Sand, plastic - Size: 4.00X1.50X1.50cm/1.57X0.59X0.59in -Note:Suitable for hose with inner diameter of 4mm. - These air stones can be used at fish tank,pond,aquarium,freshwater, saltwater aquariums, hydroponic. -Simple appearance, small size, and Air Stone will not take up too much space in the fish tank. -This aquarium air stone is delicate and home and park aquarium decoration. Suitable for freshwater, seawater aquariums, hydroponics or fish tanks. -This aquarium air stone is not only sturdy and durable, but also has good heat dissipation and filtering properties. -The aquarium bubble stone is made of high-class materials, strong and durable, and has a . Package list: 25 x air stones