My Soldier's Mailing Address?

The platoon is something your husband will have to tell you unless 21 has something to do with it, I just graduated from BCT at FLW (females aren't allowed to go to Benning for basic) and the rooster number was only used when we were in the reception battalion and for some of our paperwork for gear that we were issued. The platoon number was not given out right away and for our company if someone in another platoon knew which platoon you were in they just brought the mail over to you at the end of the day, I'm sure he will tell you ... the 21 could also be his unit # if it's not listed elsewhere o n the paper .