This visa is similar to the F-1 Student Visa except it is for vocational training. There are a wide variety of institutions accepting M-1 Students. Some examples would be a Barber Shop to Automobile Technician Schools to Electrical Training Schools.
The M-1 Vocational Student Visa will last for the length of the designated course. Your spouse and unmarried children can come to the U.S. once your visa is approved.