Features: Bubble stone Commonly known as diffuser stone (Sha Tau), a durable, good aeration, filtration. Widely used:A sewage treatment plants 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. Specifications: Main Material :Arenaceous, Plastic Color:Blue Suitable for:Fish for Tank, Aquarium Stone Size 1.50 x 2.45cm/ 0.59" x 0.96"(D x L) Connector Size 0.40 x 0.25cm/ 0.16" x 0.098"(Outer Dia x Inner Dia) Total Length 3.90cm/ 1.54" Package Includes: 1 Set(10pcs) x Air Stone note: 1.Size for manual measurement, there may be a 0 to 2 for 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!