A major advantage of C4 is that it can easily be molded into any desired shape. C4 can be pressed into gaps, cracks, holes and voids in buildings, bridges, equipment or machinery. Similarly, it can easily be inserted into empty shaped charge cases of the type used by military engineers. 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. Learn more at http://en.wikipedia.org/wiki/C-4_(explosive)