One-way valves: T-shaped structure with a single straight path for the passage of air. Ideal for use in aquariums, fish tanks, aquaculture, gardening or drip irrigation system. Compact Size: 3.8cm (L). Fits standard 4mm inner diameter air tubes. The layers on each joint make it connect tightly with the pipe to effectively prevent slipping. Free adjustment: Simply turn the knob and adjust it from closed to wide open to regulate the airflow. Anti-slip when using due to the button surface texture. Reliable Plastic: Made of durable and healthy plastic for long-term use, it does not cause any harmful effects to your lovely fishes. Extremely lightweight for effortless set up. Easy to install: Cut the air tube into 2 sections and insert the air control valve directly to connect them. Turn the knob counterclockwise to open and clockwise to close. Specifications: 4 mm Blue color Quantity delivered: 10 pieces
