Symbol 5004 from IEC 60417 - Title/Meaning: Variability Function/description: [To identify the control device by means of which a quantity is controlled. The controlled quantity increases with the figure width.]
Additional information: 
Only the linear version is given since the radius of the base of the curved version depends on the diameter of the control concerned. The curved version is shown in ISO 7000-1364.
See also symbols 5181 and 5183
Published in: First edition, 1973
Own work using: iso.org/obp/graphics/grs/1c39aa82-ae07-4266-ad07-f58c196fd0e7 200.png
Vectorization:  Mrmw