Item type: Special Sand Bar for Aquarium Air Pump Material: Mineral + Plastic Color: As picture Sizes: 4inches, 6inches, 8inches, 10inches, 12inches Package includes:1 * Special Sand Bar for Aquarium Air Pump(any other parts are not included) Features: Practical and durable home using product. 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 bubble in fish tank while attached to an air pump. Creates water currents and dazzling underwater scenes. Easy and convenient to use, perfect accessories for better life. Tips: manual measurement has some errors, please purchase carefully. 1: when you receive the bubble bar, first check whether the goods are damaged. If there is any problem with the goods, please contact our customer service to solve it. 2: the use of the bubble bar to lay, sand side up, to maintain uniform air, such as gas bar rock oblique will cause uneven or no air bubble, etc.. 3: after the connection, the trachea cannot be significantly bent and folded to prevent air from being pushed into the air bubble strip and causing air blockage Buyers need to konw 1: when used for the first time, it is normal when the bubble is larger or the air outlet is uneven. 2: before use, connect one end of the air bar stone to the oxygen pipe, and then lay the air bar stone flat on the south side of the water to blow the other end of the oxygen pipe with the mouth hard, hard repeatedly several times. Finally connect to the air pump for use. 3: oxygen air pump to gas rock in water pumping for more than 48 hours, the bubble will be fine air uniform, to achieve a good effect, the premise is that the air pump power is large enough.