: No part of the bullet or projectile can pass through to the other side.
: Formally states that UL 752 does not apply to personal protective equipment (PPE) like body armor or helmets, which remain under NIJ standards. ANSI Webstore Legacy Levels (Still Widely Referenced) ul 752 standard pdf new
Here's a brief overview:
For decades, the industry used the "Level 1 through Level 10" hierarchy. However, the new 12th edition recognizes that higher numeric levels did not always guarantee protection against threats from lower levels. The updated standard now uses threat-specific designations based on the type of firearm: : Handguns : Shotguns : No part of the bullet or projectile