What this code covers
Engine Instruments
Includes
All Engine Instruments, including Aircraft, Marine, and Vehicular; Fuel Pressure Gages; Manifold Pressure Gages; Oil Pressure Gages; Fuel Mixture Indicators; Engine Oil and Fuel Warning Devices.
Notes
Instruments designed for use on both engines and other than engines are not included in this class and should be classified in the appropriate instruments class of group 66.