Match your body armor purchase to the threats you want to be able to defeat. When planning to buy Hard Body Armour (HBA) or Rifle Plates here is some key terminology you will want to know.
Level III ICW - ICW stands for 'In Conjunction With'. This means the plates only reach a level III rating when paired with NIJ Compliant level IIIA Soft body armour.
Level III - This means the plate is tested to withstand 6 shots of 7.62x51 M80 Ball Ammunition
Level IV - This means the plate is tested to withstand 3 shots of 7.62x63 M2 APM2 Ammunition
III+, III++, Special Threat - There is no NIJ qualification for plates designated as '+' or Special Threat. These are designations unique to each manufacturer and should be carefully researched so you understand exactly what you are getting. Ask the seller if they can show test result documentation to back up the claims made about what threats the plate can defeat.
SRT (Special Rifle Threat) - Some plate do not fall under the III+ designation either. For example plates that do not stop 6 shots of M80 Ball but are designed to stop m855 green tip or any other medium calibers like 7.62x39.