The  L-1A non-immigrant classification enables a U.S. employer to transfer an  executive or manager from one of its affiliated foreign offices to one  of its offices in the United States. This classification also enables a  foreign company that does not yet have an affiliated U.S. office to send  an executive or manager to the United States with the purpose of  establishing one. 

The  L-1B nonimmigrant classification enables a U.S. employer to transfer a  professional employee with specialized knowledge relating to the  organization’s interests from one of its affiliated foreign offices to  one of its offices in the United States. This classification also  enables a foreign company that does not yet have an affiliated U.S.  office to send a specialized knowledge employee to the United States to  help establish one.