5 centistoke synthetic lubricating oil for gas turbine engines and helicopter transmissions. It is blended from high quality “hindered” esters with exceptional thermal stability properties and uses a finely balanced modern additive package to improve engine performance. AeroShell Turbine Oil 555 meets all the requirements and is qualified under US Military specification DOD-L-85734A (AS) as well as U.K. DERD.2497 and XAS-2354.