Green Vinyl Tubing - (ID) 3/16" - (OD) 1/4" - 1000 ft Made from strong and durable vinyl material, these tubes are available in a variety of sizes and lengths, great for use with air or water. The tube walls are thick and flexible, and you may also choose between the 100% opaque black vinyl, which prevents algae growth, or the clear vinyl that allow for complete visibility. If you are using accessories such as basket drippers and air stones use (ID) 3/16" instead of (ID) 1/4" Inner Dimensions: 3/16'' Outer Dimensions: 1/4''