Syringe

Replacing the Pain Pills, the Syringe provides a temporary perk where Zombies can't slow you down and you receive a faster melee with any weapon without getting fatigued. The Syringe is mostly located in the Swamp Fever Campaign. The Syringe gives you a health boost of 25 at the most. In the video below, if you look at the HUD at 0:20, you can see the Rochelle pulls out a Hyperdermic Needle and injects herself with the adrenaline. Therefore, adding more hp to the health, putting it to over a 100hp.

Video
http://www.youtube.com/watch?v=JPj3IBYIPAk