A trauma plate, also known as a trauma pack, is a plate that is an add-on component/insert to a ballistic vest. Its primary purpose is to absorb and disrupt the kinetic energy of a bullet impact and reduce the blunt trauma transferred to the wearer of the vest. Trauma plates typically enhance the ballistic value (how "bulletproof" it is) of the part of the vest that they are positioned behind.
Trauma plates are most commonly found in a pocket in front of the ballistic panel of a vest and positioned in the center of the chest. Some vests feature plate pockets in the back of the vest as well as the front. Some advanced tactical and demolition vests accommodate a multitude of trauma plates.
Trauma plates can be found in a variety of sizes and shapes. The most common shapes are rectangle, rounded rectangle and irregular hexagon.
In concealed vests (vests worn under a shirt), the trauma plates are most commonly 5″ × 8″, with variants including 5″ × 7″, 5″ × 9″, 6″ × 8″, and 6″ × 9″. Thickness (depth) varies based on material and application but rarely exceed 1/4″.