The Eagle 1, 2 and 3 are all based on the AM General heavy HMMWV ECV chassis (i.e. M1113/M1114).  The Eagle 1 and 2/3 versions are very similar except that the Eagle 2/3 have had upgrades, including added armor, reinforced chassis and more powerful engines. Although it is based upon the second version, the Eagle 3 has a different body configuration due to its design as an Artillery Forward Observation Vehicle.  These Eagle versions were succeeded by the Eagle IV ARV, which is based on the heavier/more robust DURO truck chassis.