The ceramic plates are made out of a special material (Alumina) that is both light and strong. The plates reinforce a Level III-A vest making it level III or level IV vest. The plates fit in the vest's especially designed pockets. SIZE:10' X 12' (250mm X 300mm) WEIGH: Level III apx.2.5 KG Level IV apx.3.0 KG Attach to the plate = Kevlar. Cover = Kordura by DuPont