While you are in F-1 practical training status you may apply for the H-1B work visa. This visa is what 95% of foreign students who wish to work in the U.S. obtain while in F-1 practical training status.
Another variant is the sash, which is a cloth belt designed to hold a robe together. A sash is usually tied about the waist. The Japanese equivalent of a sash, which is used for holding a kimono or yukata together, is called an obi.
The black belt is commonly the highest belt color used and denotes a degree of competence. It is often associated with a teaching grade though frequently not the highest grade or the expert of public perception. It is also a relatively recent invention (dating from the late 19th century) rather than an ancient custom.