You are looking for a dog tags boxes! First tags spawn @ 53:00 on the game clock! As long as the game clock is counting down the tags WILL SPAWN even with only one player. After someone finds and takes a dog tag you will hear a noise, the next tag spawn will be in 7-10 minutes. You must be a BF4 Premium player to pick up a tag, and you can only pick up one tag per map, (4 maps 4 tags)

Be sure to visit HJP1's IMGUR gallery for the tag spawn locations, he has done a great job with this since 2014.  http://imgur.com/a/hzBRN

The dog tags spawn in small white (whiteout and Hammer) or greyish/green (15x30cm) boxes.

Once found you need to use your regular knife to open! DO NOT use an Icicle it will destroy it!
You should see "E to interact" press E to pick up the dog tag. 

You can not use the tag until the next round!

 These are a close up of the images below!

 

 

There are four tags, one for each of the four Final Stand maps! Only one kind of tag spawns on each of the four maps, you can only pick it up once from each map. If you open another tag box you will not be able to pick it up and it will disappear in one minute. You have to wait until the round ends for the tag to show up in your battlelog, but you may leave the game early and you will get it after round ends.

 tags

Helpful Hints:

  • Do not destroy any area close to a spawn point it can make them harder to see.
  • They won't move once they spawned but can be destroyed....
  • They can spawn out of bounds (but within reach)
  • They can be invisible to some players, only way is to knife it and you will see the E
  • Your graphic setting make a difference, go as high as you can for Textures and use LOW for terrain settings to see better! (you may have to leave the game and re-enter for it to take  effect) 
  • Ground clutter can get in the way of you seeing it.
  • You can use the FLIR/IRNV Scopes, PLD or MAV on Whiteout and Hammerhead to help look, but they only glow in PLD and INRV! 4x Scope and a Flashlight work best on Hangar21 and Giants, however, they do show up with somewhat with INRV/PLD. (click on the images below to see the different views)
  • Tags will spawn with only one player as long as the game clock is running! (FACT)
  • First tags spawn about 7 mins into the game. (FACT) About 53:00 on our server.