LS-66 Sabre Direct Energy Rifle

The LS-66 Sabre Direct Energy Rifle (DER) is a weapon in Deus Ex: Human Revolution.

Characteristics
The LS-66 does not fire a set number of "rounds". Instead, it uses batteries, which have an initial charge of 500, which is about ten seconds of sustained fire. While the weapon does have an overheat gauge like the M404 Heavy rifle, it does not seem to heat up when the fire button is held, a possible bug in the initial PC release.

Jean-Francois Dugas, main designer of Deus Ex: Human Revolution says:

"It's a weapon that allows you to shoot through walls so you just have to shoot, really. Combined with the Smart Vision (augmentation to see through walls) it makes for deadly combo. However, I'm telling you right away, it's a very difficult weapon to get..."

While the rifle can fire through cover, it is not a stealthy weapon. Players should still exercise caution when using the LS-66 Sabre to this effect (i.e. firing through walls or floors) due to the noise generated both by the weapon itself and by the dying opponent. Patrolling guards who hear the attack will move to investigate and will attempt to trace the source of the shots like any other type of gunfire. Even if firing through the floor or walls, players should maintain spatial awareness of the noise generated by firing, as any guard within the noise range may approach from the player's flank to attack.

The main drawback of the rifle is its rare ammunition supply, which can complicate encounters with hostile forces where continuous fire is necessary to ensure a kills. Enemies killed by the LS-66 may undergo a short animation during their death; however, the animation can be misleading, causing players to continue firing on an enemy that is already dead. Due to the rarity of the ammunition, pulsing fire can be an effective way to budget attacks and maximize use. Additionally, targets viewed through the scope will have a red indicator light that appears when the enemy is in range; it will also cease to light up if the target is dead, making it useful in distinguishing how much continuous fire is necessary before the enemy expires.

Locations

 * One of these weapons is found behind Tong Si Hung at the Harvester hideout at the conclusion of the mission Find Vasili Sevchenko's GPL Device. You can also find ammunition (500) in a safe (the one in the container) in the hideout, and sitting on a desk (500) near where the electrified room is (by the switch to turn off the electricity).
 * In Singapore, inside of a storage room near an outdoor bot patrol shortly before Jensen uploads the virus.
 * Inside the room where Namir is fought. In the Director's Cut, an upgraded Laser Rifle is in the West Chamber behind the security glass and lasers.
 * At Panchaea, there is laser battery ammunition.
 * At the start of the level, in an orange crate with red doors high on the left-hand pile.
 * The body left of the entrance to the room where you find Taggart.
 * On the desk in the room where you find Taggart.
 * In the locker on the east side of the room where you find Sarif.

Bugs

 * Using the secondary fire key allows the player to look through the telescopic sight on the weapon, providing minor zoom and centering the laser beam on the screen. On the PC version, however, there is a bug where neither the texture for the scope, nor the crosshair appears.
 * The model for the weapon has the scope mounted on the right-hand side of the barrel, where it would be impossible for a right-handed person (eg. Adam) to use.
 * On the PC version, after completing the Missing Link, the Laser Rifle will have a laser on it, and above the ammo it will show that it has an overheat on it. It wont overheat, and the laser that it has on it does not help that much.
 * At frame rates above 90 FPS, the Laser Rifle will almost never consume ammo. This is most likely a consequence of naively rounding down ammo consumption per frame.