E1 nonimmigrant classification:
Allows nationals of a treaty country to be admitted to the United States solely to engage in international trade on their own behalf.
a
E2 nonimmigrant classification:
Allows a national of a treaty country to be admitted to the United States when investing a substantial amount of capital in a U.S. business.
E3 nonimmigrant classification:
For Australian nationals traveling to the United States to work temporarily in a specialty occupation.