I have a few of these plates. They're cheap Chinese plates however they do work quite well. Just note they do have a "foam ring" around the ceramic up to 1", this is done to save weight and cost. I probably wouldn't use them if you're someone who needs armor but they're great to throw in a spare carrier and cheaper than a lot of "training" plates. These plates are made out of UHMWPE and Alumina ceramic and can stop AP threats. These plates are made in China however are very good quality with approximately 0.400" thick Alumina Ceramic on a 0.400" thick pressed UHMWPE backer. This is similar to other armor plates. The ceramic and PE are similar to what you would find in more expensive plates. They weigh in at only 6.2 lbs each and are right around 1" thick. These plates are single-curve. Plates are 10"x12" $80 shipped for 1 plate $150 shipped for 2 plates
