Feature: 1. Nano air stone, fine bubble, high dissolved oxygen, and wider contact with the area of water. 2. Fine bubble, such as the "atomization" effect, slowly rising, good looking scenery for fish tank. 3. Adjustable bubble size, smaller the air flow, smaller the bubble. 4. Low pressure air disks, small power air pump can also produce fine bubbles. 5. Three different type for you to choose, meet your different needs. Specification: Item type: Fish Tank Air Stone DiskCondition: 100% brand newMaterial: ABS + ceramicColor: As picture shown Options: N-50, N-100, N-150 N-50 diameter: Approx. 7cm/2.8inN-100 diameter: Approx. 13cm/5.1in N-150 diameter: Approx. 15.6cm/6.1in . Package List: 1 x Air Stone Disk1 x Control valve1 x Check valve1 x Suction cup Note: Please note that N‑50/100/150 and A‑50/100/150 are the same product.Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.