Question about stab protection level on body armor.

I want to buy a concealable bullet/stab proof body armor.

When I look for bullet/stab proof body armors, most them are NIJ level IIIA for bullets and up to 7 joules for stab protection.

For stab protection vests, they usually protect you up to 24 joules for stab protection.

I having a hard time understanding this "joules" level for stab protection.

Is 7 joules strong enough to protect me from a full power knife stab from an adult man?

Submitted February 10, 2021 at 12:53AM by llst11 https://ift.tt/2ZfNku9