MASER
| Date | Clue |
|---|---|
| 2021-02-27 | Atomic clock timekeeper |
| 2019-05-26 | Atomic clock timekeeper |
| 2014-09-07 | Atomic clock part |
| 2013-09-22 | Electromagnetic device |
| 2008-11-29 | Electromagnetic wave enhancer |
| 2001-05-25 | Electromagnetic wave amplifier |
| 1998-06-24 | Part of an atomic clock |
| 1996-08-02 | Atomic clock device |