Staff Writer (Updated: 6/7/2016):
Design of the 2K12 is centered around the use of three rail-launched guided missiles utilizing an optical sight and continuous wave target illuminator. Missiles can detonate on impact or be set with a proximity fuze and hold an effective range of 15 miles against targets up to 45,930 feet in altitude. Each is powered by a solid fuel rocket motor and can reach speeds of up to Mach 2.8 which places any modern aircraft at risk. The system is categorized as a low-to-medium altitude interception device and its tracked nature assures that it can be relocated to any positions in defense of key installations. In its tracked form, the chassis makes use of six double-tired road wheels with the drive sprocket at the rear of the hull. The crew is entirely sealed in their armored vehicle while the traversing launcher - fitting the three missiles - sits atop the hull roof.
The 2K12 was modernized in 1973 to become the 2K12 Kub-M1. A further evolution of the system produced the improved 2K12 Kub-M3 of 1976. This was then followed by the 2K12 Kub-M4 in 1978 which was based on the 2K1 Kub-M3 and developed to work in conjunction with the newer 9K37 "Buk" anti-aircraft missile systems - which were inspired by the 2K12 family. The export version of the 2K12 became the 2K12E "Kvadrat" and these have since seen widespread use in Soviet/Russian-allied states and countries. The 3M9M1 became a variant in 1977 that was given an all-new tracked chassis, recognized by NATO as the "SA-6B".
Operators of the 2K12 include Algeria, Armenia, Bulgaria, Bosnia and Herzegovina, Cameroon, Chad, Cuba, Czech Republic (formerly as Czechoslovakia), Egypt, Hungary, India, Iran, Libya, Myanmar, Mozambique, North Korea, Poland, Romania, Slovakia, Serbia, Syria and Vietnam. Wide-scale use of the series by Soviet/Russian forces is no more save for a few missile target imitator systems in circulation. Iraq and the former Yugoslavia are a few other former operators of the 2K12 series. Several localized and modified versions of the 2K12 have emerged in places like Poland and the Czech Republic.
In the Soviet inventory, the 2K12 Kub was superseded by the modern 9K37 "Buk" four-missile tracked system though both were eventually used as complements to one another for a complete integrated air defense network.