Lock Joint syringe is an ammunition type in Fallout 4.


The Lock Joint syringe is a small dart used only in the Syringer, fired via compressed air to deliver powerful poisons into enemy targets. Unlike most ammunition in the game, it is located under the "AID" section of the Pip-Boy menu and has a small amount of weight.


Lead (4)
Steel (1)
Lock Joint syringe (1)


When injected into an enemy, the target will have a random chance of being paralyzed for 10 seconds. Paralyzed targets will "freeze" in whatever position they're in like statues, typically falling over, rendering them vulnerable to any attack until the effect wears off.

Weapons using this ammunition



  • Affected by Chemist perk and BioCommMesh armor mod which boost the effect up to 45 seconds of paralyzed.

Behind the scenes

The Lock Joint syringe references tetanus, also known as lockjaw and lock joint. Aside from the name, the materials required to craft this item are a nod to the common association of rusty metal to the infection. Rust itself doesn't cause tetanus, but does provide an ideal environment for the bacterium Clostridium tetani to develop.

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