| Reference Number | TPC/3/17/4 |
| Title | National (Upper) Theatre Load-Sensing Diverter Pulley-Lighting Hoists |
| Level | Item |
| Date | 25 March 1974 |
| Description | Hall Stage Equipment Ltd drawing number Y90-6. Drawn by [H A B]. Reference number K872B. |
| Extent | 1 drawing |
| Series | The National Theatre Lighting Hoists and Operating Procedure for the Lighting Hoist Control System - Olivier Theatre |