OD: 2-1/2" (63mm). Length: 3 Feet. Wall Thickness: 16 Gauge (1.65mm). HPS 6061 Aluminum 16 Gauge Straight Tubing is commonly used in industrial, automotive, marine and aerospace applications. This product is great for custom fabrication projects such as DIY air intakes, cooling systemss, turbo intercooler piping setups.