Symbol 3416 from ISO 7000 - Title/Meaning: Engine rotational speed, instantaneous decrease, off or not available Function/description: To indicate that the control that decreases the engine rotational speed is switched off or is otherwise not available for use. To indicate that the engine speed is decoupled from the transmission speed so that a decrease in engine speed does not decrease transmission speed.
pay attention to orientation of symbolAdditional information: 
Fonts shown are not restrictive.
Own work using: iso.org/obp/graphics/grs/eb1417f6-0c63-4153-ab5d-6be46df5924e 200.png
Vectorization:  Mrmw