Check the listing for details. Air Stones 2" Long Lasting Aerator Diffuser for Aquarium Hydroponics and Ponds. Condition: New. Listed at 7.99 USD. 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. Feature Fine bubble: Compared with ordinary bubble stone, creating more fine bubbles, makes the dissolved oxygen amount larger Widely applicable: Suitable for hydroponic systems, aquarium fish tanks, preventing ponds freezing in winter, helping extend the life of your nutrient solution, keep fish/ roots healthy and promote plant growth Air Stone Dimension: 2 "D; Connector Diameter: 3/16"/ or 3/8"; Recommended air pump power: > 4 W Quality material: Made of mineral material and sintered at a high temperature; Stable and durable, long lasting use ; Safe to your fish Specifications 1. Color: Gray 2. Material: Silicon carbide, plastic 3. Suitable occasion: fish tank, aquarium, hydroponics and so on 4. Size: 2" D 5. Each Weight: 4oz Notes ·Please soak the air stone in water for about 30 minutes 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.