It’s not steel, really. SURMET calls the bulletproof (yes proof) material Transparent Aluminum (a.k.a., Transparent Polycrystalline Ceramics). If this test is to be believed, TA’s advantage over glass laminate is transparent. Of course there’s glass laminate and there’s glass laminate. And how many people need to shield themselves against 50 cal.? At what cost? You can have some basic 9mm protection for cheap. Situational awareness is not so spendy either. Still, your tax dollars hard at work.