H-165 Forward Observer Module

The Target Locator is a United Nations Space Command piece of equipment. It is a compact, handheld laser pointer designed for acquiring and designating targets for small-scale orbital bombardment from an orbiting UNSC Starship, 7 Missiles are used for 1 strike. While similar in function to the UNSC Laser Designator, the Target Locator is much smaller and can be held with one hand. The Target Locator also has a scope.

The Target Locator appears as a weapon in Halo: Reach. When the trigger is held down for several seconds, a green laser beam marks the targets, and a blue circle is projected on the ground around the target area. Once the target has been locked, several large blasts fall from the sky, doing a large amount of area damage. It also seems to have limited uses as is visible in HUD images showing its use.

Trivia

 * The Target Locator appears to have a similar function to the Ion Painter and Target Painter from the Unreal series, the Hammer of Dawn from the Gears of War trilogy, and the Laser Designator from Battlefield. All are projectors that have a targeting laser used by the operator and have to be targeted for a period of time before the orbiting ship, satellite, or aircraft can launch the payload.
 * Destroying two Vehicles with a single shot from the Target Locater in the third Campaign mission unlocks the Achievement Two Corpses in One Grave.
 * The Target Locator has only been seen in Firefight and Campaign. It may not appear in multiplayer for balancing reasons. It will likely also be in Forge.
 * The Target Locator seems to reload by itself, as seen in the Skeet Shoot video posted by Bungie.