The BMP-2 is essentially an improved version of the BMP-1, incorporating a more powerful 300 horsepower engine, a 30mm cannon instead of the 73mm smoothbore cannon and the AT-3 SAGGER has been replaced by the AT-4 SPIGOT or the AT-5 SPANDREL (NATO designation.) Additionally, the turret has been enlarged slightly, which has reduced the number of infantry hatches on the back deck from four to two. Squad size has also been reduced on the BMP-2, going from eight to seven passengers. The BMP-2 comes equipped with smoke grenade launchers and has the capability of producing vehicle generated smoke through the engine. Like the BMP-1, the BMP-2 is fully amphibious, propelling itself through the water via track motion.