The LAER resembles a mix of many existing energy weapons; the barrel looks like the pulse gun, the microfusion cell is held in a basket on the bottom like a plasma rifle, the stock is similar to a laser rifle, and it displays capacitors similar to a recharger rifle. It also offers very high damage (on par with the plasma caster) for low ammunition consumption making it a great all-round weapon.
The only drawbacks of this weapon are its low critical hit damage and low item HP, so the player may have to rely on the Jury Rigging perk or weapon repair kits, especially if using over or max charged ammunition. It's worth noting that it has a very high spread for an energy rifle, equivalent to the laser RCW, limiting its usefulness at longer ranges.
When compared to its variant, Elijah's advanced LAER, the standard model could be viewed as the more practical version as it has 50% more HP, although it does shoot slower.
Another one is in the Forbidden Zone Dome, in the second floor room, just left of the brain tank.
One can be found on top of the X-13 research facility. In order to reach it, you must jump down from the cliff to the north. The cliff can be climbed by jumping up a pile of rocks just to the west of the Big MT west tunnel.
The last one, along with various energy weapon ammunition, is in the same room as above in a chamber connected to the exit platform. It is on a table in the middle of the room, and it is in good condition. This one requires a force field to be disabled in order to gain access to it.
The name implies a function like modern attempts at making electrolasers which use lasers to create a conductive plasma conduit in the air and then discharge an electrical differential across the conduit. While practical devices do not yet exist, the concept has been proven and the effect on the target is dependent upon the amount of energy delivered. At lower powers the effect would be much like a stun gun and higher energies being more like a bolt of lightning.