C-4

C-4 or Composition C-4 is a common variety of the plastic explosive family known as Composition C, which utilizes RDX as its explosive agent. C-4 is composed of explosives, plastic binder, plasticizer to make it malleable, and usually a marker or odorizing taggant chemical. C-4 has a texture similar to modelling clay and can be molded into any desired shape. C-4 is metastable and can be exploded only by the shock wave from a detonator or blasting cap.

A similar British plastic explosive, based on RDX but with different plasticizer than Composition C-4, is known as PE-4 (Plastic Explosive No. 4).