The 2B9 is an automatic 82mm mortar of Russian origin. It was introduced in 1971 in order to augment the firepower of Soviet front line troops. The full name is AM 2B9 Vasilek (Cornflower) with AM standing for Avotmaticheskiy Minomet, Russian for automatic mortar. The 2K21 complex comprises of the 2B9 and its 2F54 transport vehicle.

For a mortar the 2B9 has an unusual layout. It is based on a two wheel split trail carriage with a single outrigger at the front. The mortar looks like a cannon, is not muzzle loaded and fires from four round clips.

The 2B9 fires standard Russian 82mm mortar rounds. The maximum range is 4.3 km. The cyclic rate of fire is 120 rounds per minute. A total of 224 rounds are carried in the transport vehicle, of which 96 are ready to fire in 4-round clips.

The 2B9 can be moved over short distances on its two wheel carriage by infantry. Normally it is towed or carried internally by the 2F54 transport truck, which is based on the GAZ-66 light truck. It has also been observed mounted on top of the MT-LB tracked armored personnel carrier.

The 2B9 was used by Russia and many Warsaw Pact nations and remains in limited use. The Chinese Type W99, which is a direct copy of the 2B9, was used by Iraq and may have been sold to other nations as well.