These fuel tubing kits are commonly used for plumbing in-tank submerged fuel pumps. The flexible convoluted tubing is manufactured from PTFE and is therefore resistant to all fuel types including alcohol blends such as E85 and suitable for EFI fuel pressure. These tubes have been tested at Radium Engineering. Working Pressure: 300psi Burst Pressure: 450psi There are 2 inner diameter sizes available including 5/16" (8mm) and 3/8" (9.5mm). When installing, use a heat gun or run hot water over the ends first to loosen the material. This allows the tubing to fit snugly over the pump's outlet. Next, torque the reuseable stainless steel SAE J1508 clamps to 13.3 in-lbs.