Makes Lots of Bubbles Aquarium air stones moderate in size and outputs a large steady stream of tiny bubbles, no leaks, add enough oxygen to your fish, and also make your fish tank more beautiful. Air stones extend the life of your nutrient solution, help keep roots healthy, and promote exceptional growth. This stone is a must have for your aquariums. Specifications 1. Color: Blue 2. Material: Silicon carbide, plastic 3. Suitable occasion: fish tank, aquarium, hydroponics and so on 4. Size: 3.9" L x 0.8" W x 0.8" H 5. Each Weight: 55g/1.94oz Package Included 4 pcs air stone bars Notes Please soak the air stone in water for about 1 hour before first use. If the air stone doesn't have bubbles in one part, please change the pump of higher power. After a long-term usage, please clean it if bubbles lessen.