The specifications above are for a vehicle based on the M113A2 APC; M901s were also based on the M113A1. The M901 conversion involved fitting a "hammerhead" turret on the commander's M27 cupola which contained two TOW missile launchers and the associated targeting and guidance equipment. The missile launcher targeting head was at the end of a pivoting arm which raised the assembly for firing. When stowed, the turret was aimed down and to the rear of the vehicle; this reduced the ITV's height to 115.75" (294.00cm) for M113A2-based vehicles. Reloading was accomplished by tilting the launching apparatus back so that the crew could reach the turret through the carrier's rear roof hatch. When the ITV was modified to fire the TOW 2 series of missiles, its designation was changed to M901A1. M901s in the armored cavalry were crewed by 5 men; mechanized infantry ITVs had a crew of 4.

The various versions of the TOW missile are as follows: BGM-71A was the basic version with a 5" (13cm) diameter warhead. BGM-71C ITOW (Improved TOW) used an improved 5" (13cm) warhead and a standoff probe which allowed the shaped charge penetrator to assume a more efficient shape before it struck the target. ITOW also had an extended range of 3750m (2.33mi) compared to TOW's 3000m (1.86mi) range. BGM-71D TOW 2 has a 6" (15cm) diameter warhead, and retained a standoff probe. BGM-71E TOW 2A introduced a precursor charge in the standoff probe to defeat explosive reactive armor. BGM-71F TOW 2B is a top-attack weapon that defeats its targets with two explosively-formed projectiles that penetrate the roof of armored vehicles. TOW 2B lacks a standoff probe.

M901A3 was equipped with the RISE improvements of the M113A3.