SAAB, yes the Swedish Auto Manufacturer, has a defense division called SAAB Barracuda that develops things like this bullet proof wall. Here is their website.

The “Soft Armour” uses Lemonhead candy sized ceramic balls as the bullet proof medium. It sort of works like sandbags on steroids By up scaling sand medium to ceramic balls, the medium does not spill out like sand can out of punctured sand bags.

According to their website:

With a weight of 180 kg/m² and a thickness of 120 mm, the system protects against bursts of 7.62*51 AP ammunition (equivalent to STANAG level III).