| Clue | Source | Date |
|---|---|---|
| Bovine material in test mostly upheld as source of ventilation | The Guardian Cryptic | 13 Jun 2023 |
| Ventilation system part | Thomas Joseph | 10 Sep 2020 |
| Part of a ventilation system | New York Times | 19 Jul 2020 |
| Ventilation system part | ||
| Heat conveyor | ||
| Pipe. |