Notes: These light tanks are a rebuild of the World- War 2 era M-3A1 Stuart, with a new suspension, new diesel engine, new turret, heavier armament, and a new fire-control system. These were adopted by the Brazilian Army in the early 1970s, and 80 were delivered. The driver has a hatch on the front left side, and the commander and loader have hatches on the turret deck. The gunner uses loader's hatch. The X-1A is essentially an M-3A1 with a new engine and armament. The X-1A1 is a stretched X-1A.

The X-1A2 is an improved version of the X-1A. Improvements have been made in the turret and hull armor, night vision has been added, a laser rangefinder has been installed, and air conditioning is provided. The engine is also more powerful, to cope with the added weight, and the fuel tanks are larger. Only 30 of these light tanks were delivered between 1979 and 1983.