An SLM was a shoulder-fired anti-aircraft missile.
The SLM was loaded into a launcher tube but needed time to arm itself; the launcher user wore a with a heads-up-display tracking the target, as well as an earplug that indicated the locking procedure with sound signals.
The Sulon colonist Don Danga possessed an SLM launcher and attempted to defend his farm when it was attacked by a Corellian light freighter, but the time needed to load was against him, and he was killed when the ship's lasers hit one SLM. Later, Rebels under Morgan Katarn defended the G-Tap and Trol with Jen were part of the missile team; they had a similar death while they tried to hit the same ship.