Rheinmetall’s KF41, an IFV (Infantry Fighting Vehicle)

Composite Metal Foam is a new type of passive armor material made of thin walled hollow steel balls that are cast inside an aluminum matrix.

Its claimed to be of equal strength and effectiveness as conventional rolled homogeneous steel armor despite being 70% lighter in weight.

However, this likely only applies to full caliber steel core Armor Piercing shells and High Explosive shells.

APDS and APFSDS rounds with Tungsten/Depleted Uranium penetrators as well as shaped charges will likely pierce through this type of armor with relative ease.