Syrette

Appears in Call of Duty: World at War.

Whenever your revive a person in Co-Op or Multiplayer a syrette will appear in your hand and you will prepare it then inject the wounded player with it. It only takes 2-5 seconds.

Trivia
The Syrette probably contains morphine. If the Syrette does contains morphine, if you use it on someone two or three times,it should have killed him but it does not.
 * The Syrette doesn't appear/cannot be seen when your teammate is healing you.