I have done a lot of research on Bullet Proof Vest and Body Armor. Israeli Body Armor is some of the best you can buy. Your most protective vest is Level III-A which is the highest protection in a soft body armor. These vest do not usually have inserts for 10" X 12" hard armor plates. They will have an insert for a TRAUMA PLATE which is 6" X 8".
When you get a Level III-A external vest, these will have your inserts for your hard armor ballistic plates. The Ceramic and Dyneema are the most common and have Level III and Level IV protection. Dyneema are generally a couple pounds lighter than the ceramic plates but generally are only up to Level III.
The Level IV Ceramic will protect you against Armor Piercing .30 caliber rounds. I hope this info helped . I will be happy to list what these plates protect against also if anybody has a question See Ya..