| Reference Number | TPC/3/19/3 |
| Title | Quadruple Up-Down Detector with Dead Space ~CD245 |
| Level | Item |
| Date | 01 July 1978 |
| Description | Evershed Power-Optics Ltd drawing number V4506. Original date c 1974. |
| Extent | 1 drawing |
| Series | The National Theatre Lighting Hoists - Olivier Theatre |