Laser Sight

"Laser sights here!"

- The Survivors

The Laser Sight appears in Left 4 Dead 2 as a tool used to enhance the accuracy of primary weapons. The laser can be attached to any primary weapon, but not to secondary weapons.

The Laser Sight cannot be transferred to other weapons if the Survivor grabs a new gun. An example is having a Laser Sight-equipped to a Combat Rifle and picking up another Combat Rifle; the new Combat Rifle will not have a Laser Sight.

Tactics

 * A Laser Sight improves most weapons considerably, but your best bet is to attach one to an AK-47 or Silenced Submachine Gun. Powerful but highly inaccurate weapons that fires fast becomes devastating when paired with Laser Sights. It also increases the accuracy of all weapons rather than just improving your aim.
 * Shotguns aren't for long-range anyways, which goes against the purpose of Laser Sights.
 * The arc of Grenade Launcher effectively makes this almost useless.
 * If the player can't use the Sniper Rifle or Hunting Rifle accurately, Laser Sights may enhance their aim.
 * For Hunting Rifle, Sniper Rifle, and Grenade Launcher, only their moving accuracy is improved.
 * Other players can see your Laser Sight even when you are behind them, making it easier for them to avoid stepping into your line of fire, which is essential in difficulties allowing friendly fire.
 * Laser Sights are incredibly rare. Hold on to the gun as long as you can when you have one and avoid swapping your weapon. If not all of the team have Laser Sights and a Survivor with one dies, it is a good idea to salvage the weapon to take full advantage of the sight.
 * Regrettably, you cannot attach a Laser Sight to sidearms. Only main weapons can benefit from Laser Sights. Fortunately, this also means that you can swap your secondary weapon without losing your Laser Sight.
 * Laser Sights are incredibly useful in Realism Mode, making it much easier for Survivors to find each other without silhouettes.
 * Unlike Explosive and Incendiary shots, but similar to Foot Lockers and Ammo Piles, an unlimited amount of Laser Sights can be obtained from every single pile of them, so if you find a better weapon shortly after attaching one, you can go back to upgrade your new weapon.
 * While rare to find both in a single level, the M60 benefits greatly from the addition of a Laser Sight, allowing it to land more shots, not to mention each individual shot is already deadly.
 * The Survivor Bots are capable of finding Laser Sights themselves, but are not too likely to actually announce it. In fact, they usually just take the Laser Sight and then return to the player(s) without a word. If you suddenly notice the Survivor Bots are equipped with them, it might be a wise choice to examine the area for the sights.

Behind the Scenes
Laser Sights were originally an upgrade in Left 4 Dead, but was unused in the final version. However, mods on the PC version allow the Survivors to use these, which lets players use the Laser Sight in Left 4 Dead.

Accessibility
The Laser Sight is a very rare find. Players can often play most campaigns without spotting a Laser Sight at all. The only areas that will always have the Laser Sight is Whitaker's Gun Shop in Dead Center and under Memorial Bridge in the 3rd chapter of Cold Stream. Swamp Fever also has a high chance of spawning Laser sights if playing from start to finish. In the first level of Dark Carnival, a Laser Sight may spawn on the motel roof near the billboard where a Hunting Rifle is found. However, Survivor Bots are unable to make their way to it without assistance because being closer to a player is a higher priority.

Another example where Laser Sights are often found is in the second level of Dark Carnival near the area where Gnome Chompski is found on one of the game stalls or in the bathrooms. They can be found in all campaigns. Since the Laser Sight cannot be transferred from weapon to weapon, the ideal solution is to equip it to a weapon the player intends to keep.

Usually, if the AI Director decides to spawn one, Laser Sights will generally only appear once per campaign. However, it is possible that two will spawn. Sometimes, those two will be in separate chapters of the campaign, and other times they may appear together in the same chapter of a campaign, such as Whitaker's Gun Shop and in a tent after the crescendo.

You can easely get it just by pressing (') and typing (ent_create upgrade_laser_sight). At the console.