In the U.S. Army, a Light, Heavy, or Stryker Infantry company Fire Support Team (FIST) consists of a Fire Support Officer (FSO), a Fire Support Sergeant, three Forward Observers (FO), two Fire Support Specialists and three Radio Telephone Operators (RTO).
In the U.S. Marine Corps, scout observers also act as naval gunfire spotters and call for, observe and adjust artillery and naval gunfire support, and coordinate fire support assets to include mortars, rockets, artillery, NSFS and CAS/CIFS.