327 / | HD | MISCELLANEOUS ACTIVE ELECTRICAL NONLINEAR DEVICES, CIRCUITS, AND SYSTEMS |
524 | DF | SPECIFIC IDENTIFIABLE DEVICE, CIRCUIT, OR SYSTEM {22} |
598 | DF | .~ With particular tube structure {2} |
601 | ![]() | .~.~ Gas tube {1} |
602 | DF | .~.~.~> With particular electrode arrangement |