The P.R.L. 412 must be unlocked before it can be used. It is unlocked by beating the main game on Professional mode. Once unlocked, the weapon is free when the player starts a new round on any completed game.
The P.R.L. 412 takes up 21 spaces (7x3) of Leon's inventory, making it one of the bulkiest weapons in the game. It is equivalent in size to the Chicago Typewriter. The weapon has no listed stats and cannot be upgraded.
The weapon has 2 settings, a flash, where you just aim and fire, or a charged blast. This weapon has a meter that shows how charged up the weapon is when you hold the fire button. If the meter glows red, release the fire button and you can take down any boss or enemy with ease. Once fired, the weapon must recharge its basic energy pool, so you can't just blast away with flashes, or continuously charge the main laser.
The basic mode of fire for the P.R.L. 412 is a short-ranged pulse of light, which damages and stuns enemies, much like a flash grenade. This flash can destroy most enemies in 3-4 hits. It can also kill some creatures with just the flash, like the Verdugo and even Osmund Saddler. When charged up, the P.R.L. 412 fires a penetrating laser beam that pierces and kills most enemies in one shot. It can also take down groups as in the Wii version, it has a recoil force, so you basically don't have to aim, though that decreases your overall accuracy. However, when fully charged, the full laser sight is shown, making it decent for long-range shots.
PS2 & PC versions
"This custom light-based weapon is tuned to harm only the Plaga, leaving the human host undamaged. Charged shots have narrow range but are powerful."
Wii & HD ports
"Use the charge attack to decimate all surrounding enemies with this supremely powerful laser weapon!"
In the PlayStation 2 and PC version, the P.R.L. 412 cannot damage or affect any inanimate objects, including barrels, chains, switches, etc.
In Resident Evil 4 HD, which is based on the Wii version of the game, the P.R.L. will lock onto and destroy most crates, bear traps, dynamite traps, and blue medallions, and destroy them (though the counter which keeps track of the number of blue medallions will not appear on-screen if the medallion was not the primary target). When in the area of the Pearl Pendant over the filthy water, the P.R.L. will destroy the wood holding up the lid and will then cause the pendant to fall in the same shot.
- The P.R.L. 412 eliminates the need for flash grenades, which can be sold to the Merchant for extra money. However, the flash of the P.R.L. 412 has a shorter range than a flash grenade, so exercise caution.
- Its light burst is effective against groups (in a straight line or tightly packed) and kills difficult enemies, such as Regeneradors, Iron Maidens and Gatling Man in one charged blast, one of the 2 weapons able to do so, the other being the Rocket Launcher.
- There are only two enemies in the entire game able to survive a charged blast from the P.R.L. 412:
- El Gigante: The first blast will weaken him and reveal his Plaga; another blast to the Plaga itself will finish him off.
- U3: The first blast will deplete most of its health, but it will continue to attack in its second form. However, the beast can then be killed with a single hit from any weapon (even the Knife).
- Since what actually kills Las Plagas is not the visible spectrum of light but the UV light, the weapon is most likely firing intense light (whether in a blast or a straight line) of the UV spectrum with some of it being visible as blue / violet light, which is what comes after UV in the light spectrum.
- It is interesting that the description for the P.R.L. 412 states that as a weapon, it only targets the Plagas inside a host, and not the host themselves, stating that the host is not harmed. Since it only works on fully matured Plagas, this is not possible, and as such, even simple Ganado are killed by the weapon.
- The weapon itself is non-canon, being an after-game addition unlocked to make it more fun for those who completed the game. In the storyline, research into removing the Plagas only went as far as the machine used to remove the parasites from Leon and Ashley, which used a form of radiation.
- Hamamura, Koichi, ed (2006) (in Japanese). biohazard4 kaitaishinsho revised edition. Famitsu. ISBN 978-4-7577-2638-3.
- Chicago Typewriter - another unlockable weapon in Resident Evil 4
- Handcannon - ditto
- Infinite Launcher - ditto