It is a compact, lightweight device which easily fits in your pocket or bag. Alternatively, carry with special bags or clothing clips.
Its outer casing makes it comfortable to use, while its strong laminate inner wall is hard enough / safe to carry around.
An elastomeric pump is a medical device used to inject drugs.
Depending on the treatment required, these medications may include antibiotics, chemotherapy, 5FU, cytostatic, analgesics, and local anesthetics.