Symbol 5385 from IEC 60417 - Title/Meaning: Beam limiting device, open Function/description: To identify controls for opening the beam limiting device or to identify its partially or fully open state.
Additional information: 
Published in: Supplement G, 1985
Own work using: iso.org/obp/graphics/grs/a4c3f025-4c5c-482a-a701-c30bc93f67fb 200.png
Vectorization:  Mrmw