Knox chest protection is courtesy of a low-profile Micro-Lock chest protector to fit all Knox Armoured Shirts and Jackets. CE certified to EN 1621 – 3. All are available as aftermarket upgrades to existing body armour.  Micro-Lock offers a snug, soft fit to the wearer but thanks to its SMART technology it locks in the case of an impact and absorbs a significant amount of energy before it gets to the wearer’s torso.