The lubricants covered by this specification are military unique. The lubricated oils are intended for use in the precision bearings of inertial guidance gyros, accelerometers and other suitable instrument bearing applications. To allow the user the option of using a specified oil with the optimum viscosity and operation temperatures for the application, the lubricants in this specification are classified into five different grades of oils according to their viscosity properties. Prior to using these oils, their performance should be verified in each application. Recommended ambient temperature ranges for the five grades of oil are shown in table VI. The lubricants covered by this specification were formulated for use in critical military applications, such as aircraft, systems, and various weapon systems. Because of its specific applications and harsh temperature range, there are no other commercial specifications available to cover these military applications.