100% brand new and high quality Bubble stone Commonly known as diffuser stone (Sha Tau), a durable, good aeration, filtration, and widely used:A sewage treatment plant for aeration and Stirring to prevent large particles of sediment deposition, and removal of some organic matter. Aquarium (fish farms) eutrophic water body increase oxygen into the environment, bio-farming increase oxygen Live fish and seafood transport increase oxygen. Aquarium (purifiers) purification, filtration and water quality ozone sterilization and aeration. Other required air diffusion process uses. Main Material :Arenaceous, Plastic Color:Blue Suitable for:Fish Tank, Aquarium Stone Size 1.50 x 2.45cm/ 0.59" x 0.96"(D*L) Connector Size 0.40 x 0.25cm/ 0.16" x 0.098"(Outer Dia*Inner Dia) Total Length 3.90cm/ 1.54" Note: Suitable for inner diameter 4mm soft tube. Before use, please immerse it in the water for 15 minutes. It it doesn't have bubbles in one part, please change the pump of higher power. It will not work as normal if you attach to the submersible pump. Quantity:1Set(10pcs) NOTE: 1.Size for manual measurement, there may be a 0 to 2 cm error, belongs to the normal phenomenon. 2.And due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1Set(10pcs) x Air Stone