“24KGB” means “24-karat gold bonding” in short. Using this method, layers of 14- or 18-karat gold are put on top of layers of 24-karat gold to make a cheaper copy.
Most of the time, bronze is used as a base for gold bonding. The base material is then covered with layers of 24-karat gold, which are then covered with layers of 14- or 18-karat gold. The result is a material that looks, feels, and bends a lot like 14- or 18-karat gold, but doesn’t cost as much. “Gold filled” or “gold overlay” are other names for gold bonding.