TOS-1 (Russian: ТОС-1 - тяжёлая огнемётная система, English: Heavy Flamethrower System) is a Soviet 220mm 30-barrel (original system, Ob.634 or TOS-1M) or 24-barrel (Ob.634B or TOS-1A) multiple rocket launcher and thermobaric weapon mounted on a T-72 tank chassis. TOS-1 was designed for defeating enemy personnel in fortifications, in open country, and in lightly armoured vehicles and transport. First combat tests took place in 1988-1989 in the Panjshir Valley during the Soviet war in Afghanistan. The TOS-1 was shown for the first time in public in 1999 in Omsk.
The TOS-1 is not used by the artillery units of the Russian Armed Forces but is found in NBC defense units (Russian: войскa радиационной, химической и биологической защиты (РХБЗ)).