The cuticle is largely composed of protein and α‑chitin, covalently bonded to form polysaccharides of N‑actylglucosamine monomeric units.
It is important to understand that the physical properties of the cuticle can be dramatically altered by chemical processes.
Whilst the cuticle is initially soft and flexible, these processes can be used to harden and strengthen it.
The two processes relevant to crustacea are sclerotisation and mineralisation.