The SS-4 was the first Soviet strategic missile using storable propellants and a completely autonomous inertial guidance system. With its capability to deliver a megaton-class nuclear warhead the rocket provided a capability to attack strategic targets at medium ranges. This system constituted the bulk of the Soviet offensive missile threat to Western Europe. It was deployed at both soft launch pads and hard silos.
The SS-5 was a single-stage, storable liquid-propellant, intermediate range ballistic missile. As with the SS-4, the Skean missile was a single stage missile with integral fuel tanks though it was larger and twice the maximum range.