Symbol 5722 from IEC 60417 - Title/Meaning: Grey scale Function/description: To identify the control or the indicator to change the image grey scale, for example on diagnostic ultrasound equipment.
Additional information: 
Published in: Amendment 2, 2002,3C/473/FDIS,62A/228/CDV
Own work using: iso.org/obp/graphics/grs/8d9a50c0-e54f-4eec-a551-a3b3c2054796 200.png
Vectorization:  Mrmw