I am a 13F and have been for 10 months now. Right now Im attached to a mechanized infantry unit. Im a team chief and I have another dismount that is my radio operator. You could be working with a Bradley, Stryker, or a Hummer doing different missions. In todays war, you wont be doing the classical desc. of your job but sometimes you might be sent out with a sniper squad or on convoys or doing intelligence gathering. You can also get sent to Joint Fires Observers COurse in OK where you will be trained to call in close air support and close combat aircraft which is a real hot thing in the 13F world now. Promotion points are real low and there is a selective re enlistment bonus available.