December 17, 2007: The U.S. Army and Marines are in the process of replacing existing SAPI (Small arms protective inserts) ceramic bulletproof plates for protective vests, with thicker, but not much heavier ESAPI plates. The new ESAPI provides protection from armor piercing bullets, which enemy snipers are increasingly using.

The basic "Level 3" SAPI plates are 10x12 inches, weigh 4.6 pounds each and cost about $400. A lighter weight (3.3 pounds) plate costs $750. The older Level 4 plates, weighing about 6.4 pounds each, could stop armor piercing bullets, but the new ESAPI weighs less and have the same stopping power. ESAPI is more expensive, at $600 a plate. There are also smaller plates that can be worn on the side. Despite pressure from politicians to force the troops to wear the side plates (which constrict movement and add weight), the generals dug in their heels, and were allowed to let local commanders to decide if side plates had to be worn.

SAPI are made of boron carbide ceramic with a spectra shield backing. This combination causes bullets to fragment and slow down before getting through the plate. Occasionally, some fragments will get through, but these are stopped by the layers of Kevlar that make up the flak jackets. The success of the plates, and the frequent attacks on U.S. troops in Iraq has led the U.S. Army to try and get enough plates for all troops in the combat zone, not just those in infantry units. This is more of a morale issue than anything else, as non-infantry troops are most frequently exposed to bombs and RPGs. The fragments from these weapons can be stopped by the flack jackets without the plates. But morale is important, so the army is trying to get enough SAPI plates for everyone.

The ceramic plates require a manufacturing process that uses, and produces, a lot of toxic chemicals, much of the production has moved to China.