Manufactured by Soviet State Arsenals in the mid-1950s. This gun was the next larger version of the B-10 and was a towed piece used for direct and indirect fire. It was commonly towed by a 6x6 ZIL-157 truck or a UAZ 4x4 truck. Bulgaria, Cambodia, China, East Germany, Egypt, Iraq, North Korea, North Vietnam and Poland are some of the countries that used the weapon. Although declared obsolete, this gun can still be found in arsenals in the Middle East and Africa.