What is meaning of the C4 bomb?

C4 is made up of explosives, plastic binder, plasticizer and usually marker or odorizing taggant chemicals such as 2,3-dimethyl-2,3-dinitrobutane (DMDNB) to help detect the explosive and identify its source.

The explosive in C4 is RDX (cyclonite or cyclotrimethylene trinitramine), which makes up around 91% of C4 by mass. The plasticizer is diethylhexyl (5.3%)

or dioctyl sebacate and the binder is usually polyisobutylene (2.1%). Another plasticizer used is dioctyl adipate (DOA). A small amount of SAE 10 non-detergent motor oil (1.6%) is also added.

C4 is manufactured by combining the noted ingredients with binder dissolved in a solvent. The solvent is then evaporated and the mixture dried and filtered. The final material is an off-white solid with a texture similar to moDELLing clay.