That's up to you. When you enlist, you'll choose a job—known as a Military Occupational Specialty (MOS), which is Guard speak for “your job.” Every job title in the Guard has a code, using a number and letter. For example, a Cavalry Scout is MOS 19D (19 Delta).—from more than 150 options in several career fields. Aviation, Infantry, Military Police (MP) and Public Affairs are just a few of the many fields we offer.