Keep your aquarium's air flow running smoothly with these premium stainless steel check valves. Measuring 4.6cm in length, these one-way valves are designed to connect with 4*6mm tubing and prevent unwanted backflow in your aquarium's air pump system. The durable stainless steel construction ensures long-lasting performance, while the clear directional arrow indicator makes installation straightforward. Perfect for CO2 systems and air pump setups, these non-return valves help protect your equipment and maintain consistent airflow. The pack includes 2 valves, providing a reliable solution for maintaining optimal conditions in your aquarium. These precision-engineered components are essential for any serious aquarium enthusiast looking to maintain a stable and efficient air delivery system.