Symbol 5712 from IEC 60417 - Title/Meaning: Variation of ultrasound energy Function/description: To identify the control or the indicator to increase or decrease the emitted ultrasound energy.
Additional information: 
If a separate control is used to either increase or decrease the emitted ultrasound energy, the symbol element for variability may be replaced by a ""plus"" (+) or ""minus"" (-)
Published in: Amendment 2, 2002,3C/473/FDIS,62A/228/CDV
Own work using: iso.org/obp/graphics/grs/231a4923-5ee2-49a6-b42f-fce6901fb1bd 200.png
Vectorization:  Mrmw