The SA-7 GRAIL (Strela-2) man-portable, shoulder-fired, low-altitude SAM system is similar to the US Army REDEYE, with a high explsive warhead and passive infrared homing guidance. The HN-5 ( Hong Nu = Red Cherry ) is an improved Chinese version with upgraded capabilities. The SA-7 was the first generation of Soviet man portable surface-to-air missiles. Although classed as "fire and forget" types, the missiles were easily overcome by solar heat and, when used in hilly terrain, by heat from the ground.

The SA-7 seeker is fitted with a filter to reduce the effectiveness of decoying flares and to block IR emissions. The system consists of the missile (9K32 & 9K32M), a reloadable gripstock (9P54 & 9P54M), and a thermal battery (9B17). An identification friend or foe (IFF) system can be fitted to the operators helmet. Further, a supplementary early warning system consisting of a passive RF antenna and headphones can be used to provide early cue about the approach and rough direction of an enemy aircraft. Although the SA-7 is limited in range, speed, and altitude, it forces enemy pilots to fly above minimum radar limitations which results in detection and vulnerability to regimental and divisional air defense systems.

The SA-7a (9K32 Strela-2) was introduced into service in 1968, but was soon replaced by the SA-7b (9K32M Strela-2M) which became the most common production model. The SA-7b, differs from the SA-7a primarily by using a boosted propellant charge to increase range and speed. The SA-7a had a slant range of 3.6 km and a kill zone between 15 and 1500 meters in altitude, with a speed of about 430 meters per second (Mach 1.4). The SA-7b has a slant range of about 4.2 km, a ceiling of about 2300 meters, and a speed of about 500 meters per second (Mach 1.75).

Both the SA-7a and SA-7b are tail-chase missile systems, and its effectiveness depends on its ability to lock onto the heat source of low-flying fixed and rotary-wing aircraft targets