What are some gift ideas i can send to my marine for his 21st birthday?

my boyfriend is a marine and is right now in Afghanistan. his b-day is in a month. he will be turning 21. im thinking of sending him a birthday package. im going to include a birthday card, a picture of me, a corona pinata with candy,however i don't know what else to include. we've only been dating for 6 months so i don't want to give him something too big. i was planing on giving him a dog tag locket but im not sure if its appropriate. what do you suggest i should add in the package besides sex coupons.