C4, or Composite 4 explosives, is a type of plastic explosive available for the Grenadier. It has a detonation velocity of 8,092 m/s (26,550 ft/s).
C4 is very stable and insensitive to most physical shocks. C4 cannot be detonated by a gunshot or by dropping it onto a hard surface. It does not explode when set on fire or exposed to microwave radiation. Detonation can only be initiated by a combination of extreme heat and a shockwave, such as when a detonator inserted into it is fired.
Multiple bricks of C4 can be placed and detonated simultaneously.