Description: High Dissolved : This Air Pump Stone bar can release a large number of fine bubbles, increasing the contact water area, driving cycling of water, increasing the amount of dissolved . Fine Dense Bubbles: Durable frosted material of the aquarium bubble stone with small air outlet can release fine and dense bubbles, creating a atomization effect. Universal Applications: The back of the Air Pump Stone bar bubble diffuser made of delicate and durable ceramic is with connector to suit fish tanks of various sizes. Using Instructions: The Air Pump Stone bar is used to increase in fish tanks, and is used with tubes and pumps. Please soak Air Pump Stone bar in water for 15 minutes before use. For long term use, if the is clogged and the air bubbles are reduced, it can be cleaned and used repeatedly. Tips for use: When all the accessories of the air pump are connected, repeatedly unplug and insert the pipe on the back door to add water to the water pipe, and the atomization effect can be quickly achieved. Specification: Material: Ceramic Size Chart: Small: 10cmx4cm/3.94inchx1.57inch Medium: 20cmx4cm/7.87inchx1.57inch Large: 30cmx4cm/11.81inchx1.57inch Package Includes: 1 Aquarium Air Pump Stone Note: Please allow slightly errors due to manual measurement and different monitors.