HPS 2.5" - 3" OD 16 Gauge 6061 T6 Aluminum Step Up Transition Joiner with 4" Length are commonly used in industrial, automotive, marine and aerospace industry; Great for custom fabrication project such as DIY welding, high performance air intake kit, cooling radiator and heater systems, turbo intercooler piping and charge pipe setup. 6061 aluminum is the most popular and versatile alloy, and is the least expensive of the heat treatable aluminum alloys. HPS aluminum round tubing step up transition reducer joiner is sold in the T6 condition, ideal for sawing, machining, sanding, and polishing. The aluminum step up transition joiner tube can be polished, but due to the softness of the aluminum, care must be taken not to remove too much material, especially in the area near any welds. Product Specification: Product Type - Aluminum Step Up Transition Joiner. Material: 16 Gauge 6061-T6 Aluminum. Tubing Outside Diameter: 2-1/2" - 3" (63mm - 76mm). Length: 4". Tubing Inside Diameter: 2-3/8" - 2-7/8" (60mm - 73mm). Wall Thickness: 0.065" (1.65mm). Remark: HPS does NOT recommend 6061 Aluminum to be used for exhaust systems.