The metal frame balance bike is a type of balance bike that has a frame made of metal material, such as aluminum or steel. Metal frames are typically stronger and more durable than plastic frames, making them suitable for heavier children and more intense use. Metal also offers better resistance to wear and tear compared to plastic. However, metal frames are typically heavier than plastic frames, making them harder for young children to maneuver. The choice between metal and plastic frame balance bikes ultimately depends on the child's weight and riding conditions, as well as the parent's preference and budget.