In order to maintain F-1 status, students are are limited to work for 20 hours per week.
Off-campus employment
OPT (Optional Practical Training) One year of full or part time off-campus employment associated with your academic area of study that may be used both before and after completion of the degree.
CPT (Curricular Practical Training) Full or part time off-campus employment that is an “integral part” of a course. This is available only before completion of degree.