Description: Product: This Aquarium CO2 Bubble Counter with Check Valves is designed specifically for CO2 Regulator Systems, serving as an essential tool to ensure a aquatic environment.(Note that this does not completely stop the reversal)with Check Valves: CO2 Bubble Counter features a built in check valves that effectively prevents liquid from flowing back when the pressure changes, ensuring that the water plant table and CO2 bottle are not damaged.Detachable: The CO2 Bubble Counter is detachable, making it easy to clean and maintain.Clear Tube: Clear tube designs of the bubble counter allows for easy counting and measureing of CO2 bubbles, providing great control over CO2 output.Easy to Use: This Aquarium accessory is easy to install and operate, making it a user friendly addition to any CO2 Regulator System. Size Chart: 7.8cmx2cm/3.07inchx0.79inch Package Includes: 1CO2 Bubble Counter Note: Please allow slightly errors due to manual measurement and different monitors.