Tracker for short, is any Marine associated with an "Amphibious Assault battalion" ie; crewman, mechanic armorers,communication tech Etc... All are considered amtrackers. Amtracs is short for amphibious tractors or AAVP7A1 the current model. Soon to be replaced by "expeditionary fighting vehicle" as seen on YouTube or history channel. E-4 C 2141 Bco 3rd AAV BN !st Mar Div