Brand new and high quality.Suitable for freshwater， saltwater/reef aquariums and hydroponic use.Unique design and fine durability.Increase oxygen levels and PH， lower CO2.An important instrument to successfully keep aquatic fish for respiration process.Suitable for any form of aquarium. Total length: 3.9cmBottom diameter: about 0.8cmTop diameter: 1.5cmMaterial: silicon carbide superhard corundum sintered by high temperature Color: sent randomly Package:6 x Air stone