UHMWPE (Ultra High Molecular Weight Polyethylene)
Ultra-high molecular weight polyethylene (UHMWPE) laminate is used as a bullet stop material and is incredibly strong - 15 times stronger than steel, in practice - extremely durable and 40% lighter than para-aramids. 
The polyethylene (UHMWPE) vest meets the NIJ 0101.06 standard and Level 3 A specifications. A vest  weight is 1,5 Kg. max.

Polyethylene (UHMWPE) vests are much more comfortable to wear, softer and lighter than Kevlar and ceramic plate vests.