The 2S12 "Sani" ("sleigh") (GRAU index 2S12) is a 120 mm heavy mortar system used by the Russian Army and other former Soviet states.

[3] First fielded in 1981, the 2S12 is a continued development on the towed mortars first used in World War II.

2S12 is in fact the designator for the combination of the 2B11 "Sani" heavy mortar with its transport vehicle 2F510, a GAZ-66-15 4×4 truck.

The 2B11 weighs nearly 200 kg (500 lb) when fully assembled, and thus must be mounted to the 2×1 wheeled chassis 2L81 and towed to the emplacement site by the truck.

[6] 2S12A got a new "Ural" family transport vehicle with high power diesel engine and electric hoist for loading the mortar and a new base plate with a hinge that allows for pointing horizontally without turning the heavy support.