Improved First Aid Kit
Standard issue to all US military with only minor variations between services and units, the IFAK is a small, self-contained trauma kit intended to be used for the emergency treatment of the person carrying it.
Most of the things inside the IFAK are self-operable to at least some degree, so that a conscious casualty can treat themselves if necessary. Everybody has their own IFAK, and you are not supposed to use your own IFAK supplies on a casualty unless you've used up the stuff in theirs already.
Typically contains Israeli bandages, a nasopharyngeal airway (NPA) sized to the carrier's head, KY Jelly lubricant for the NPA, a self-operable tourniquet (known as a "CAT" - Combat Application Tourniquet), re-hydration salts, and a few other pieces and parts like 2" medical tape and rubber gloves.
Units often set a standardized mount point for the IFAK on each member's body armor or web gear, so that everyone knows where everyone else's is.