Check the listing for details. VIVOSUN 4"/5"/8" Air Stone Disc w/ Shell & Suction Cups for Fish Tank Hydroponic. Condition: New. Listed at 9.49 USD. About 4" Air Stone Fine Bubbles: The air stone disc produces lots of dense fine bubbles; A great way to oxygenate your hydroponic growing systems, ponds, aquariums and enliven the aquatic life Size: 4" - 4" D x 0.8" H; Recommended air pump power: 4 - 16 W; Standard ID airline tubing: 0.16" / 4 mm; 3 strong suction cups easily fix it in the smooth aquarium Durable Material: Made of mineral material and sintered at a high temperature; The material is sturdy and durable which is safe to your fish ExtenEasy to Use: Soak the stone completely in water for 2 hour before use; Clean it regularly with a brush as they get clogged after weeks or months of usaged the life of your nutrient solution, help keep fish / roots healthy, and promote plant growth Widely Applicable: Fit for hydroponic systems, ponds, aquariums or fish tanks and other systems