A bulletproof vest of a high protection class consists of two elements: a ballistic fabric sewn together plate carrier and special protective plates that are inserted inside and act as a shield for the chest and back.
To trap a bullet or fragment and dissipate its energy are able: a metal plate (made of steel, titanium or aluminum-based alloys) and a ceramic plate (made of aluminum oxide, boron carbide or silicon carbide).
As for the steel plates, the vest with such elements of protection has high strength, as well as being resistant to repeated hits. And the cost of such body armor is cheaper than that of Kevlar. A significant disadvantage – when hit by a bullet, the steel plate gives splinters, which can damage limbs and head. This problem can be solved by covering the steel plate with an aramid sheath – it will hold back the flying splinters.
Another disadvantage is that a flak jacket with steel plates is a bit heavy. Its weight is about 10 kg.
Unlike steel plates, aluminum and titanium alloys do not form splinters when hit by a bullet. Such plates weigh less. But also the degree of their protection is lower.
Ceramic plate, the production of which uses aluminum oxide, boron carbide and silicon carbide, can withstand even armor-piercing bullets. The main disadvantages: when hit by a bullet, the ceramic cracks and in subsequent use no longer guarantees the original degree of protection. The cost of the ceramic vest is relatively more expensive, so it is not widely used.
But this does not detract from its advantages – the ceramic plate reliably protects the body and has a relatively small weight.
Armor plate with this name indicates that it is made of ultra-high molecular weight high-density polyethylene. Polyethylene plate is able to withstand a 9 mm bullet, which corresponds to the third class of protection. At the same time a bulletproof vest with such a plate does not weigh much.
The disadvantages are the high flammability of the material and the thickness of the plate is about 2 cm, which is a lot. If you have to wear a bulletproof vest under your clothes, this option is unlikely to be suitable.
Modular flak vest
There are vests that allow you to quickly change the configuration of the protected zones and their area. These are so-called modular models. They are additionally equipped with a neck-shoulder block and a groin protection that are made of several layers of ballistic fabric. They can be quickly fastened by means of Velcro fasteners.
There are situations when it is better to have an armor kit. It includes a lightweight cover, which in everyday life will act as a vest of class 1-2. But if necessary the special pockets in the case can be fitted with armour plates providing a higher degree of protection. Such a vest can be quickly upgraded with a ceramic or steel plate, and after the threat has passed, it can be returned to its lightweight state.