In Shingeki no Kyojin, the soldiers use the 3D maneuver gear to attack the Titans and cut the back of their necks. In the last episodes, I have seen that they use a balloon of gas as the power to release the chains to climb the walls and trees. How does this exactly work? Is the gas the only power supply to release the chains?

4 Answers 4


There's several components to the 3D gear that are separate and operate independently. Not all aspects of the mechanics have been revealed in intricate detail, but there is a pretty good idea of the overall operation.

The short answer is that, yes, it is essentially all gas-powered. The trigger causes the gas to shoot the wire out, and a gas compression is also what shortens the wire to pull the device's user forward.

Operating device

The operating device is what the user holds (where the triggers are located). The mechanics of this are not known, and are described as being a black box.{2} Use of this component is what allows the others to function.

Grapple piston

Once the user pulls a trigger, it activates a piston{4} within the main device. This piston uses a quick spurt of compressed gas to fire forward the grapple hook toward its target.{nt.1} No other power source is necessary for this to happen due to the intense compression release from the piston.


The user's grapple hooks fire from a coil{1} which is located in the device itself. When the user wishes to move forward, their gear must quickly pull the cable back into the device. This is done via a fan mechanism{3} that is also gas-powered. Basically, when the user wants to wind back up, the compressed gas blows into the fan, spinning it rapidly and coiling the wire back up, pulling the user forward.

Currently Disclosable Information, Episode 8, card 2

References and reading

  1. Episode 8, card 1
  2. Episode 8, card 2
  3. Episode 9, card 1
  4. Piston at Wikipedia
  5. 3D maneuver gear at the Shingeki no Kyojin Wiki
  6. Note 1: Episode 8's second currently disclosable information states that the gas is "compressed ... and injected"{2}, but this appears to be a grammatical error; see comments below.
  • 1
    About the note on "injected": The corresponding Japanese does not say about ejection. A more literal translation is like "Gas is injected into the cylinder, under compression." (No surprises there, actually.)
    – Asahiko
    Commented Aug 28, 2013 at 0:49
  • @Asa Fair enough, my note was an assumption (considering that's how it's expelled from the tank to be useful in the machine).
    – Cattua
    Commented Aug 28, 2013 at 1:08

I have a good idea on how the black box works. The top trigger is used for the hook and the bottom trigger is used to activate the gas with the one fan on that side therefore turning the operator. The two switches on the side are used to extend and reel in the operator on the wire that is attached to the hooks. If you have any other ideas please let me know, I saw Levi do this in one of the OVA's that is how I figured it out. If you want the link just let me know. http://watchsnk.net/2014/09/shingeki-no-kyojin-ova-gaiden-kuinaki-sentaku-no-regret/ This is a simple theory since it was only for aprox. 10 seconds, it starts at 17:47

  • 2
    You should include the link in your answer as a reference.
    – Jon Lin
    Commented Jun 25, 2015 at 17:15

For the Black Box mechanism (grips) the curved trigger (shaped like a brake lever on a bicycle) located on the outside of the grip is used to fire the grappling hooks towards the target. The top trigger within the grip is used to release the grappling hooks or to reel them back towards the user pulling the user towards the target. The bottom trigger within the grip is used to activate the gas propulsion system that helps the user move around with speed on the ground or in the air. The sliders placed near the top of the grip are used to change the angle and position the shooters on the users hips are facing letting them target where to fire a grappling hook. SOURCES: NO REGRETS OVA- Levi using ODM Gear.


I've been looking into this and I do consider it feasible. The retraction system checks out but some issues I have thought of (and are pretty obvious) are that it would be very heavy with the compressed gas on you, (practical use you wouldn't need the sheath or the blades cause titans don't exist).

To shoot a hook out with just compressed gas you wouldn't get very far especially if it's steel you would have to use something a lot lighter like carbon fiber. (I hadn't thought of pistons till I read one of these answers though). How much gas you can release out of the pressure tanks at once is pretty small with current technology so you couldn't get much of a boost from it but if you found a way to release gas faster without blowing yourself up then that would solve a lot of problems.

That all I really have on the subject, I really want to build some 3DMG but it will be a very drawn out project because it will cost a lot. I don't have and links that really would help describe any of this.

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