| 313 / | HD | ELECTRIC LAMP AND DISCHARGE DEVICES | 
| 326 | DF | ELECTRODE AND SHIELD STRUCTURES {14} | 
| 348 |  | .~ Foraminous electrodes (e.g., grids) or shields {2} | 
| 349 | DF | .~.~> Nonuniform mesh area or nonstraight electrodes or nonuniform cross sectional area electrodes | 
| 350 | DF | .~.~> Rods, wire, or mesh supported on rod or post |