Airline Available in: 3/16", & 1/4" 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 choose between the 100% opaque black vinyl, which prevents algae growth, or the clear vinyl that allow for complete visibility. 3/16" = Inner Dimensions: 3/16", Outer Dimensions: 1/4" 1/4" = Inner Dimensions: 1/4", Outer Dimensions: 3/8"