color displays as well as the radar upgrade and the IFF system. In 2011 a Kub upgraded launcher (named "2K12 KUB CZ") with three Aspide 2000 missiles in launch containers was presented at the International Exhibition of Defence and Security Technologies (IDET) exposition in Brno. The modifications were made by Retia. Description The 2K12 system shares many components with the 2K11 Krug (SA-4) system. In many ways they are designed to complement each other; 2K11 is effective at long ranges and high altitudes, 2K12 at medium ranges and intermediate altitudes. The system is able to acquire and begin tracking targets using the 1S91 "Самоходная установка разведки и наведения" (SPRGU - "Self-propelled Reconnaissance and Guidance Unit" / NATO: "Straight Flush" radar) at and begin illumination and guidance at . IFF is also performed using this radar. It can only guide one or two missiles to a single target at any time. The missile is initially command guided with terminal semi-active radar homing (SARH), with target illumination provided by the "Straight Flush" radar. Detonation is via either the impact or proximity fuze. On the latest models, this vehicle is also fitted with an optical tracking system which allows engagement without the use of the radar (for active RF emissions stealth reasons, or due to heavy ECM jamming) in which case the effective altitude is limited to 14 km/46000 ft. The optical tracking method also allows engagements to altitudes below that where the radar is able to track targets. Maximum target speed is around Mach 2 for head-on engagements and Mach 1 for tail-chase engagements. Top speed of the missile is approximately Mach 2.8. In contrast to the elaborate Patriot missile or even the simpler Hawk system fielded by US forces, most of the system rides on two tracked self-propelled vehicles, rather than towed or mounted on trucks, and either the launcher or control vehicle can be set to launch in only 15 minutes after changing location. Missiles The fairly large missiles have an effective range of 4–24 km (2.5–15 miles) and an effective altitude of 50–14,000 m (164–45,931 ft). The missile weighs 599 kg (1,321 lb) and the warhead weighs 56 kg (123 lb). Top missile speed is approx. Mach 2.8. The combined propulsion system 9D16K included solid fuel rocket motor which, when burned out, forms the combustion chamber for a ramjet in a pioneering design putting this missile far ahead of