A model support letter for Form I-140, Immigrant Petition for Alien Workers, based on a certified PERM application. This letter is used by an employer to describe the job offer and the employer's and foreign worker's qualifications to US Citizenship and Immigration Services (USCIS) under the employment-based second (EB-2) or third (EB-3) preference category. This Standard Document has integrated notes with important explanations and drafting tips.