The M6 Spartan Laser is a shoulder-mounted direct energy weapon used by the UNSC. It fires an extremely powerful red laser, capable of destorying vehicles and infantry with one accurate strike. When the trigger is pulled, a targeting dot is projected. The laser will then charge for three seconds before firing its powerful and destructive burst.

NOTE: A new weapon for Halo 3, this is perhaps taking the place of the fuel rod gun, which is conspicuously absent from Halo3.com. Bungie here seems to have exchanged a slow-moving projectile that follows an arc with a fast-moving one that travels straight, but takes time to charge.

It's a mystery why it is referred to as a Spartan Laser-- perhaps it was developed primarily or exclusively for use by Spartans?