Iskander Missile SS-26 Stone is a short range tactical missile system developed and produced in Russia. The system replaces the Oka SS-23 SPIDER which had been terminated under the Intermediate Nuclear Forces (INF) Treaty. Development of the system was undertaken by the Kolomna Engineering Design Bureau development during the 1990s under the project name "Tender". The Iskander SS-25 Stone theatre missile system is designed to destroy enemy weapons, command posts, communications nodes, tactical aircraft parked on airfields, air and missile defence installations and other critical targets in operational depth round the clock and in any season when countered by heavy regular and precision-guided munitions, weapons of mass destruction, as well as anti-missile defence and EW assets. All Iskander vehicles feature cross-country wheeled chassis making them very mobile. The missile is solid-fuelled, single-staged with continuous guidance along the whole trajectory. It features a non-separable warhead with a self-contained INS coupled with an optical homing head. The warhead can house a cluster-bomb, HE-fragmentation or penetration charge.