In some cases, U.S. businesses wish to employ foreign workers that have special skills or fulfill a certain niche on a temporary or limited-duration basis. In these cases, the U.S. business will sponsor the foreign worker, and will file a petition on behalf of the foreign worker (the beneficiary). The most common is the H-1B employment-based nonimmigrant visa, but others include H-2A, H-2B, H-3. Temporary foreign workers from Canada and Mexico may qualify for a TN visa, which is based on the NAFTA Treaty.