NICAD
| Date | Clue |
|---|---|
| 2024-05-15 | Battery type |
| 2022-08-26 | Common kind of battery |
| 2021-12-25 | Battery type |
| 2018-11-11 | Kind of battery |
| 2014-01-27 | Hybrid kind of battery |
| 2008-10-10 | Certain dry cell, briefly |
| 2006-03-15 | Battery type |
| 2001-12-21 | Certain battery |
| 2000-11-23 | Kind of battery |