The 9K31 Strela-1 is a self-propelled SAM system of Soviet origin. In the West this system is better known by its NATO reporting SA-9 Gaskin. The 9K31 was designed to complement the ZSU-23-4 self-propelled anti-aircraft gun as a regimental asset.

The 9K31 is based on the BRDM-2 4x4 chassis. The driver and commander are seated in the front and the gunner in the turret. Up to four launch container can be attached to the turret. During travel the missiles are lowered. The 9K31 is a stand alone system, but usually it operates in pairs or groups of four. Target information is relayed by radio by other air defense systems.

The turret is fitted with four 9M31 Strela-1 surface to air missiles with infrared guidance. The maximum effective range is 4.2 km and maximum altitude is 3 km. Due to the limitations of the seeker the maximum range can only be achieved under favorable circumstances. Effectiveness during head-on engagements and at night is much reduced.

The steel armor protects from small arms fire and shell splinters. The 9K31 is operated under full armor protection, except for reloading the missiles. An NBC system is fitted while smoke grenade dischargers are not.

The BRDM-2 chassis provides a high road speed and reasonable cross country performance. Since the belly wheels are not fitted the cross country capability is slightly less. A 140 hp petrol engine provides propulsion. The 9K31 is fully amphibious.

The 9K31 Strela-1 was very common during the Cold War. While the 9K31 is cheap and a stand-alone system it was widely exported to nations with close ties to the USSR. In Russia and most Eastern European systems the 9K31 was replaced by the 9K35 Strela-10 (SA-14 Gopher), but the 9K31 remains in widespread use around the world.