We have a patent pending on the GC Shield - a light, flexible shield that can stop a 9mm or .357 Magnum bullet - that also fits in a school bag. GC Shields can also be linked together to form a Shield Wall - to protect groups, e.g. classrooms.
Here is a photo of the front of the GC Shield, after eight shots with 9mm bullets - including two in the same spot (in the lower right-hand corner):
And here is the back of that GC Shield - you can see that not only have all the bullets been stopped, there is also limited back-face deformation - or in plain English, the bullet impacts haven't made the back of the shield bulge out too much, and thus body damage from the shock wave of the bullet has been limited.
GC armour is comprised of alternating layers of GC graphene/aerogel and other bullet- and stab-resistant materials; this graphic shows the multi-layer structure:
The key difference between how GC composite armour works versus other armours is force dispersion. Other armours (e.g. steel, Kevlar/Dyneema, ceramic) stop a bullet by the sheer strength of their materials - but the impact force of the bullet remains concentrated in a tight cone that travels through the material itself, often causing a spall effect where bits of the material break off on the other side of the impact.
In contrast, GC composite armour works by dispersing the force of impact over a much larger area; thus each successive layer of GC composite dissipates the impact forces more, slowing a bullet down until it stops. There is much less (if any) spalling that occurs with GC composite armour.
In the high-speed (25,000 frames per second) video below, you can see this force dispersion in action; when the 9mm bullet hits, you can see how the shock wave quickly spreads out from the point of impact, dispersing the bullet's energy much more effectively than with conventional armours. This works even with much higher energy bullets - next is a .357 Magnum, followed by a12-gauge, 1-ounce rifled shotgun slug with over 4,000 Joules of impact energy (more than a 7.62mm NATO round or a sniper bullet) hitting our GC Shield; you can see how our shield both quickly dissipates the energy and then stops all of these rounds. Also note that these are multiple shots. Only the GC Shield with our patent-pending graphene/aerogel nano-composite technology has achieved this level of force dispersion per weight.