Symbol 6087 from IEC 60417 - Title/Meaning: Latch to specific group, general Function/description: [To identify the control of the group to be latch to.This symbol should be used in the orientation shown.]
Additional information: 
This is a generic symbol.
The letter symbol “A” is to be replaced by a typical character, for example, a group containing mathematical symbols is indicated by a not-equal sign.
Own work using: iso.org/obp/graphics/grs/c00748f2-d0a9-4c61-a724-3c83b61dbc5c 200.png
Vectorization:  Mrmw