Protip: you can tell the S-54 apart from the S-55 by the lack of muzzle break, lack of IR lamp, taller loader's hatch (for the removed 12.7mm anti-aircraft machine gun mount), and mushroom-shaped armor dome for the ventilator fan.
Protip: you can tell the S-54 apart from the S-55 by the lack of muzzle break, lack of IR lamp, taller loader's hatch (for the removed 12.7mm anti-aircraft machine gun mount), and mushroom-shaped armor dome for the ventilator fan.