Ceramic Plates (Boron/Silicon Carbide): These plates work by shattering the incoming bullet. The extremely hard ceramic material blunts the bullet's tip, breaking it into pieces, while the layered backing material catches the fragments. They are excellent against armor-piercing (AP) rounds but are heavier and can degrade after multiple hits in the same area.
Polyethylene (UHMWPE) Plates: These ultra-high-molecular-weight polyethylene plates work by deforming and trapping the bullet. The fibrous layers stretch and absorb the kinetic energy. Their biggest advantage is being exceptionally lightweight (up to 50% lighter than ceramic for the same protection level), offering great mobility. However, they can be vulnerable to extreme heat and certain AP rounds.
The Hybrid Solution: Many manufacturers now offer hybrid plates. These often feature a ceramic strike face to break up the bullet, fused to a polyethylene backer to catch the fragments and reduce weight, offering a balanced performance profile.
NIJ Standard Compliance: Regardless of material, all plates must be tested and certified to rigorous standards like NIJ 0101.06, which specifies protection levels (Level III, IV) against specific ammunition threats.
