Feature: 100% Brand new and high quality A great way to properly aerate a home aquarium, help to keep fish healthy and adds to the beauty of the aquarium. Increase oxygen levels, lower CO2 and raise pH It is an important instrument to successfully keep aquatic fish for respiration process Durable, washable and sintered by high temperature, different from other air stones Creates bubbles in fish tank while attached to an air pump Creates water currents and dazzling underwater scenes Easy and convenient to use. Description Material: Gravel, Plastic Size: 0.59*0.39in Color: As picture shown Usage: Before use, please immerse it in the water for 15 minutes. After a long-term use, clean your stone regularly so that it will be most effective. If the air stones just have bubbles in one part, please change a pump of higher power. Package Included: 2PC Air Stone Bars Note 1.Our size are Asian Size,1-2 size smaller than euro size,please choose your size according to the size chart. 2.Due to the hand measurement, there have size error about 1-2 cm.Item color displayed in photos may be showing slightly different