PVC Aquarium Tubing: The airline tubing is made of pure PVC material. It is really flexible and scratch-proof. Its thickened design allows for rough handling and repeated use. Multipurpose: The aquarium airline tubing is ideal for most basic aeration setup. Great for fish tanks, aquariums, hydroponics, ponds, water gardens, siphon systems, laboratories, etc. Standard Size Airline Tubing: 328 ft. in length in length and 3/16" in diameter (4 mm in inner diameter & 6 mm in outer diameter). Work great on most common air systems, such as oxygen, CO₂ or other high-pressure systems. Kink-Resistant: The wear-resistant aquarium hose can be freely twisted without kinking. The smooth interior surface effectively prevents sediment accumulation and allows for smooth air flow. Safe & Reusable: The fish tank PVC tubing is safe and reliable to resist cracking, high temperature, corrosion and leakage. Dependable for long-time use. 328 Feet Standard 3/16" Tubing for Fish Tank Air Pump Flexible Kink-Resistant Pure PVC Hose for Aquarium Garden Terrarium Pond