I can't figure out which of the plates they sell is the ATT A-101. I don't think that they actually sell it. I think that they just used it to get onto the NIJ's list, thus fooling people into thinking that their products are more legitimate than they actually are.
This is pure cringe: http://americanblastsystems.com/nij-level-iii-stand-alone-2-6-lbs-ballistic-plate/
"Protection Level: NIJ III ammo 7.62×59 AK47 MSC, NATO Stand Alone"
7.62×59 AK47 MSC, NATO.
As for the Level IV plate, here's something for comparison's sake.
Hesco's BI-4800 is their top-of-the-line plate. It costs over $1000 per unit. It's rated to Level IV, and it weighs..... 5.1 pounds in a size M SAPI.
Armor Express' Abrams H IV SA is their top-of-the line plate. The MSRP is over $2000 per unit, and it's well over $1000 per unit even with bulk quantity discounts. It's rated to Level IV, and it weighs..... 5.0 pounds in a size M SAPI.
TPG's BLACK LVL IV Elite Series is their top-of-the line plate. It costs well over $1000 per unit. It's rated to Level IV, and it weighs..... 4.8 pounds in a size M shooter's cut, which would be somewhere slightly over 5.0 pounds in a SAPI size M.
And you're telling me that the guys responsible for "7.62×59 AK47 MSC, NATO" and the 1.6 pound ICW* plate, are capable of making a $300 Level IV plate at 4.5 pounds? If you believe that, I've got some oceanfront property in Nebraska I'd like to sell you.
Nah, it's a Chinese plate with a huge foam ring. It doesn't use the expensive and exotic materials that those more costly plates use, and its ceramic coverage is probably around 80 square inches or less. As such, it's very cheap to make.
Hesco could copy that risible technique and release a "2.5 pound Level IV plate"! But Hesco actually have integrity. They wouldn't stoop so low.
* - ICW a 3.5 pound backing plate!