Single Way Valves: T-shaped structure with a straight single way for air to pass through. Ideal for use in fish tanks, aquariums, aquaculture, gardening, or drip irrigation systems. Compact Size: 3.8 x 2 cm. Compatible with standard 4-6 mm ID airline tubing. Layered joints ensure a tight connection with the hose to help prevent disconnection. Free Adjustment: Easily twist the knob to adjust from closed to fully open, allowing control of airflow. Knob features a textured surface for improved grip and slip resistance during use. Reliable Plastic: Constructed from durable and safe plastic material suitable for long-term use. Lightweight design allows for simple setup and installation. Easy to Install: Cut the air tube into two sections and insert the air control valve to connect them. Turn the knob counterclockwise to open and clockwise to close.