The 9K116 Bastion (AT-10 STABBER) is a laser-beam riding, antitank missile launched from the main gun of a T-55AM2B main battle tank, BMP-3 Infantry Fighting Vehicle, and the MT-12 antitank gun. The 9K116 system uses beam-riding laser guidance. The 9K116 uses the 9M117 missile. The ammunition for this system is designated 3UBK10 for the T-55, and 3UBK12 for the BMP-3. This ammunition consists of the 9M117 missile and a propellant sleeve which fits over the rear end of the missile. As a result, the complete 3UBK10 resembles a normal round of 100-mm ammunition. The 9M117 missile has two sets of pop-out fins, a rear set for stability and a front set for steering. For the MT-12, the missile is called the Kastet, and requires that the MT-12 have a special laser designator mounted nearby to provide the necessary guidance. The missile has a 80% probability of hit at 4000 meters. Armor penetration is 550-600 mm of RHA, and the projectile has an effective envelope of 100 to 5000 meters.