When designing armor capable of stopping a bullet, the two most important factors are weight and resistance to penetration, and they’re often at odds with one another. A thick steel plate can stop many projectiles but at some point the weight becomes impractical for most applications.

Now, new research into a novel type of material is showing promise as both an option for powerful protection and a weight-saving replacement for heavy metal plates. It’s a composite metal foam which saves weight but seems to offer protection similar to solid steel, and it could be the next big thing in vehicle armor.

The material is made of up countless tiny metal spheres which are actually hollow inside. A layer of ceramic is added to the outer surface of the metal, forming a plate. The shape of the tiny balls inside helps the material absorb the kinetic force of a projectile and protect whatever might be sitting behind it, like passengers in a vehicle.

What makes this new material so great is that it’s less than half the weight of a solid steel plate that would provide similar protection. This means that armored vehicles equipped with the composite material could be much lighter while offering the same protection to those sitting inside.

Going forward, the researchers say that the material could be made even better optimized, potentially offering even greater protection while limiting weight.

“These findings stem from testing armors we made by simply combining steel-steel CMF with off-the-shelf ceramic face plates, aluminum back plate and adhesive material,” Afsaneh Rabiei, co-author of the research, said in a statement. “We only optimized our CMF material and replaced the steel plate in standard vehicle armor with steel-steel CMF armor. There is additional work we could do to make it even better. For example, we would like to optimize the adhesion and thickness of the ceramic, CMF and aluminum layers, which may lead to even lower total weight and improved efficiency of the final armor.”