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The EMP Tool, also referred to as the Alyx, is an electromagnetic pulse[1] multitool mainly used by Alyx Vance for several purposes.


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Mossman freeing Gordon with Alyx's EMP Tool in Breen's office.

Half-Life 2[]

  • The device is always attached to Alyx's belt, and she regularly uses it to bypass Combine security systems or open locked doors. It can also be used to gain access to Combine computers and information they store, giving the Resistance pivotal information on the Combine.
  • In Episode One, Alyx also uses it to re-program Rollermines to attack Combine troops, Zombies, Overwatch Snipers and Stalkers, allowing Gordon and her to proceed further towards the core. This function may be done in a similar way that it is used to hack the Combine computers.
  • All of the previous functions are done by an electric pulse tunneling from the EMP Tool to the nearest electric conductor. The Combine's somewhat superfluous use of technology to manage and control the City makes this function highly useful.
  • The tool can also be used to store information, much like an USB key of sorts. Alyx uses it to store Judith Mossman's message and encrypted files about the Borealis, which she delivers to Isaac Kleiner for analyzing at White Forest. To download or upload data, it is simply a matter of plugging it into a computer and copying the required data.
  • At the end of Half-Life 2, Judith Mossman threatens Breen with it, hinting that the tool can be used as a weapon against living objects, possibly to electrocute or stun them. However, it may be that it simply looks threatening. After scaring off Breen, Mossman uses it to free Gordon Freeman from his cell, possibly via a similar method used to open locked doors.
    • However, when Judith Mossman uses the tool to disable Breen's radio, when he tell the Guards to "Get in here", he appears to rub his hand, as if it were burned, reinforcing the possibility that the tool can be used as a weapon.

Half-Life: Alyx[]

  • A redesigned version of the multi-tool, nicknamed the "Alyx," is used by the player to solve holographic puzzles to unlock doors and loot, and to disable laser trip mines. Its design is similar to the EMP Tool, but with a red and white rotating head (used for hacking) and no extending arms.
  • It is likely that this "Alyx" multi-tool becomes the EMP Tool over time, as the "Alyx" multi-tool contains trace amounts of Combine tech already, and is probably improved upon by Alyx Vance over time.

Behind the scenes[]

  • While it is never named in-game, its name is given by its texture file, named "emptool_sheet", and its model, named "alyx_EmpTool_prop".
    • The sound files of the discharge are named "alyx_stunner" and are stored within the Stun Batons sound folder.
  • The cut Roller Wand may be a predecessor to the EMP Tool.
  • The functionality of the EMP Tool seems to resemble the "Sonic Screwdriver" from Doctor Who


  • If Alyx is killed the EMP tool will remain in the air for two seconds before disappearing.


List of appearances[]


Imagecat The Half-Life Wiki has more images related to EMP Tool.
  1. Half-Life 2 Prima Guide