Symbol 1321B from ISO 7000 - Title/Meaning: Mass; weight Function/description: To indicate mass. To identify a function related to mass.
pay attention to orientation of symbolAdditional information: 
ISO 8100-1
Own work using: iso.org/obp/graphics/grs/800ea1ff-0704-4f49-9b5e-b6e56ffef2b7 200.png
Vectorization:  Mrmw