H-165 Forward Observer Module

The H-165 FOM or Target Locator is a United Nations Space Command artillery fire designator. The Target Locator is a compact, handheld laser emitter designed for acquiring and designating targets for small-scale precision rocket artillery support. 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 both 2x and 4x magnification.

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 red circle is projected on the ground around the target area. Once the target has been locked, 7 missiles strike the designated area from above, doing a large amount of area damage.

The Target Locator can also lock onto an individual target, with the projected circle following the target until the strike commences.

Trivia

 * Destroying two vehicles with a single fire mission from the Target Locator in the mission ONI: Sword Base unlocks the Achievement Two Corpses in One Grave. This is similar to the Halo 3 Achievement Two for One, which is unlocked by earning a Double Kill with the Spartan Laser, another anti-vehicular specific weapon, as well as the weapons needed to unlock the achievement were introduced in their specific games, e.g. the Target Locator in Halo: Reach.
 * The Target Locator is available only in Firefight and the Campaign mission ONI: Sword Base. It does not appear in Matchmaking or Forge for balancing reasons.
 * The Target Locator available on the Firefight map Unearthed carries three shots instead of two.
 * If infinite ammunition is enabled, the Target Locator will still deplete but, if it has zero shots remaining and the reticule has become a cross, one can continue to fire the Target Locator and HUD rings will appear on the ground as if a target had been designated. However, no rounds will impact the ground. Also, If bottomless clip is enabled, the Target Locator can still create HUD rings on the ground while it is reloading without any cooldown, though no rounds will impact the ground if another location is already designated.
 * Even when the Target Locator's fire missions are depleted, a player can still pick them up. This may be because the gun is so rare that it was never programmed to not be equipable. After every round in Firefight, if the player still holds the Target Locator, 2 shots will be added. This may also explain why it can be picked up after being emptied.
 * The fire mission is composed of seven missiles, another reference to Bungie's frequent usage of their favorite number, seven.
 * Upon acquiring a target lock with the locator, a radio message will often be received by the player from the artillery crew such as "target acquired" or "fire for effect". The phrase "Firing FPF One" can also be heard, and is likely an altered replay of the conversation in Exodus.
 * After a certain period of time (usually several minutes), an additional shot will be added to the locator. This is only available in the level, ONI: Sword Base.
 * During Firefight, additional shots will be added only after the completion of a round.
 * A common exploit among players on ONI: Sword Base is to wait for a checkpoint and target a swarm of enemies. After having all enemies killed, granting a large kill streak and a sum of credits, the player would restart the checkpoint and repeat the same action. This would grant players infinite credits if continued, though this exploit has been patched and the weapon can no longer grant credit bonuses during campaign levels to prevent cheating. This is called "Credit Farming."
 * While it may be unintentional, the target beacon is a red ring; when missiles rain down, every living thing will die. This may be a reference to one of the most famous, or rather infamous, Xbox 360 glitches, the Red Ring of Death.
 * For some reason, the player's character will grunt or make a sound of pain when the target locator is fully charged and locked, most likely because the recharge time uses similar game mechanics as an overheating weapon, such as a Spartan Laser.
 * Targeting a Phantom is nearly useless, as one strike will not destroy it, and there is rarely time to target it again.
 * There is a rare chance a player can target a large projectile

List of appearances

 * Halo: Reach