<b>Features: </b><br> Widely applicable: Suitable for hydroponic systems, ponds, aquarium fish tanks, helping extend the life of your nutrient solution<br> Air Stone Dimension: 1.5 "D x 0.6" H<br> Fits for 3/ 16 inch standard airline tubing<br> Quality and safe materials: Made of safe and washable material<br> Disk-shaped design makes it easily be hidden in your aquarium or other fish tank bubble decorations (Note: Soak them at least for 2 hours before use) <br> <b>Dimension: </b><br> Air Stone Dimension: 1.5 "D x 0.6" H<br> <b>Package includes: </b><br> 4 PCS air stones <b>Note: </b> <br> Soak them for at least 2 hours before use and clean regularly by a brush as they get clogged after weeks or months of usage