These are charms or amulets that were worn by Africans for protection against thunderbolts and disease, to acquire wives, and to advert all sorts of disasters. The term is perhaps derived from the Arabic safi (“pure, select, excellent”).
The charms were composed of slips of paper containing passages from the Koran, and sometimes intermixed with Kabbalistic symbols. They were placed in silver tubes or bags and worn next to the skin, often attached to a dress or other articles of clothing. They also were popular with both sexes regardless of the person’s religion. A.G.H.
Source: 9, 1451.