Pretty tough stuff! This clear armor is made by South Carolina-based ArmorLine Corp, which describes this as a spinel transparent ceramic. The ArmorLine rep in the video says the plates are one-half the thickness and one-half the weight of conventional, laminated “bullet-proof glass” with similar projectile-stopping power. On its web page, the company says it is building “the world’s largest manufacturing facility dedicated exclusively to the development, scale-up, and high-volume production of transparent spinel ceramic materials”
Adding some info from one of our readers … “Wanted to give some background the on-line tech update on transparent spinel. In the late 1960s. Prof. Hayne Palmour III and his colleagues at N. C. State University with assist from Kodak made transparent spinel on a R&D contract from either the Air Force or the Army (probably the Army as I recall helicopter windows was the aim). The spinel powders were derived from sulfate precursors that resulted in transparent purple spinel.” This reader was one of Palmour’s students.