An optional upgrade of the Zone trooper and Zone raider armour, the scanner pack was a set of sophisticated sensors and scanning equipment that increases the armor's sight and weapon range capabilities as well as limited detection of active camouflage systems.
Although the brief description reads "detects stealth in a small raduis," the detection range is comparable to if not greater than defensive structures like the Watchtower, Guardian cannon and AA Battery. Combined with the Zone infantry's resistance to rockets, crushing and Tiberium, as well as their excellent anti-armor capability, the ability to detect stealth makes them that much more dangerous.
Behind the scenes
In configuration files, they are named AutoInjectors, indicating they are actually integrated into the wearer's body.