Symbol 2726 from ISO 7000 - Title/Meaning: Drops per milliliter Function/description: On medical devices: to indicate the number of drops per milliliter. That means the design of the drip tube in the drip chamber of the system.
pay attention to orientation of symbolAdditional information: 
The number of drops per ml is specified. ""20"" is shown as an example and should be replaced by the correct number of drops per ml. This symbol utilizes ISO 7000-1056.
Own work using: iso.org/obp/graphics/grs/68ef33cc-be32-42d7-bc6f-ade2df6ed5db 200.png
Vectorization:  Mrmw