Check the listing for details. AquaNeat 12 Pcs Air Tank Hydroponics.. Condition: New. Listed at 4.95 USD. THIS IS A BRAND NEW ITEM IN ITS FACTORY SEALED BAG.X00210RDVZ AQUANEAT 12 pcs LONG-LASTING Air Stone, Aquarium Fish Tank Aerator Diffuser Hydroponics · Description Key Feature: Widely applicable: Great for freshwater, saltwater/reef aquariums and hydroponic use; Increase oxygen levels, "blow off" CO2 and raise pH; Can be easily driven by even nano air pumps Material: Durable and sturdy material; Safe to your fish Dimension:; Fits standard airline tubing aquarium and CO2 tubing with inner diameter of 3/16"(4mm) Note: You have to soak it in water for about 30 minutes before connecting to an air pump to run it Includes: 12 pieces of gray air stones Product description 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. Material: Silicon carbide, plastic 2. Suitable occasion: fish tank, aquarium, hydroponics and so on Package Included: 12 pieces of air stones: 0.80" D x 2.00" H. (20mmx50mm) 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 Return Policy: 14 Days, In Original Condition, Full Refund Less S&H.