Final answer:
The number of "V" devices that can be worn on a ribbon depends on the specific military awards and criteria.
Step-by-step explanation:
In the context of medicine, the question is not clear. The term "V devices" usually refers to a bronze or silver letter"V" attachment that can be worn on a ribbon or badge to denote valor or combat distinction in the United States military. Therefore, the number of "V" devices that can be worn on a ribbon would depend on the specific military awards and criteria. For example, a military service member may receive multiple awards that qualify for the "V" device, but each award may have different rules about the number of devices that can be worn on the ribbon.