Good Morning, One of the best kept secrets about ballistic protection is HDPE. High Density Poly-Ethelene. You probably have some of this "...body armor..." at home and don't even realize it. Go into your kitchen and look for a white plastic cutting board. A 3/4 inch thick piece of HDPE will stop a 230 grain .45 ACP dead in it's tracks, is will only penetrate about 3/4 of the way thru. I can just hear the hoots now, "...what a moron...". If you purchase two sheets of 3/4 inch HDPE and Gorilla Glue a 1/4 inch sheet of Aluminum between them, you will be surprised, should you fire thru this with a chronograph on the far end. Your average .223 or .308 rifle round may get thru, but it is far from lethal. HDPE is not light, but, it's lighter than a sheet of Boron-Carbide level 4A plate. And you can heat it in the over and mold it to fit about any contour. Body armor is line NODS/NVG, it can be a game changer. Don't scrimp. The folks at "BulletProofMe" can assist you over the phone, and more often that not, over the phone will discuss military over runs in stock at substantial savings. But if you are looking for a low cost, low weight, engine block saver. Look no further.