The Armed Forces Vocational Aptitude Battery (ASVAB) is the entrance test to enlist in the US Military. You can't enlist in the US Military without taking the ASVAB.
The ASVAB has two primary purposes: First, it determines whether you have the mental aptitude to enlist in the military branch of your choice, and second, the results help the service(s) determine which military job(s) you have the mental aptitude for.
