Marina 3-Way Air Flow Control Valve – A gang valve that allows you to run up to three air-driven devices from one aquarium air pump. This plastic 3-way valve splits the air output into three adjustable outlets. Each outlet has its own little knob so you can control the airflow to each airstone, filter, or ornament independently. It’s perfect for fine-tuning the amount of bubbles or air in different parts of your tank, and it’s easy to install in-line with standard airline tubing.