2 x 2.5" (OD) Straight aluminum pipe. 2 x 2.5" (OD) 90 Degree aluminum pipe. 2 x 2.5" (OD) 45 Degree aluminum pipe. 2 x 2.5" (OD) U Shape aluminum pipe. High-Quality Aluminum Construction – Made from durable, lightweight aluminum for superior performance, corrosion resistance, and heat dissipation, helping your turbo system operate more efficiently.