| 73 / | HD | MEASURING AND TESTING |
| 488 | DF | SPEED, VELOCITY, OR ACCELERATION {29} |
| 514.01 | DF | .~ Acceleration determination utilizing inertial element {8} |
| 514.05 | DF | .~.~ Fluid or fluent material {4} |
| 514.06 | ![]() | .~.~.~ Fluid or fluent material support of an inertial element {2} |
| 514.07 | DF | .~.~.~.~> Gas |
| 514.08 | DF | .~.~.~.~> Magnetic fluid |