Symbol 5183 from IEC 60417 - Title/Meaning: Variability, maximum step Function/description: [To identify the control element by means of which a quantity, for instance speed, heating power, freezing temperature, depression, can be changed. The maximum value of this quantity can be temporarily switched on by an additional operation.]
Additional information: 
The curved version is shown in symbol 6020.
See also symbols 5004, 5181 and ISO 7000-1364
Published in: Supplement O, 1996,3C/295/DIS
Own work using: iso.org/obp/graphics/grs/2130731b-f4cc-4161-a1ca-4a2a71531ead 200.png
Vectorization:  Mrmw