http://www.ar500armor.com/ar500-armor-body-armor/level-iii-body-armor-en.html

Our Level III+ body armor features an improved ultra hard ballistic steel core further enhancing performance over our level III line, with nearly a 30% increase in core strength. All while maintaining the same industry leading stand-alone, multi-hit performance and stress fracture resistance as our level III body armor. Capable of defeating higher level rifle threats, Level III+ armor offers enhanced ballistic protection against 5.56x45 M193, 5.56x45 M855/SS109, and 7.62x51 M80 Ball (.308) rifle threats up to 3,100 feet per second, and 7.62x51 AP (Black Tip).

Our new generation II design on all of our level III+ body armor improves ergonomics and comfort. Every curve and cut has a purpose; to improve comfort, maximize protection of your vitals, and minimize weight.