The levels, such as IIIA, III, and IV, refer to the National Institute of Justice (NIJ) standards for ballistic protection.
- Level IIIA: Protects against handgun rounds up to .44 Magnum.
- Level III: Offers protection against rifle rounds, like 7.62mm NATO or .308 Winchester
- Level IV: Provides the highest level of protection, stopping armor-piercing rounds such as .30-06 M2 AP
These levels help users choose the appropriate armor based on the threats they might face.