The inner circle (plug) is composed of two layers aluminium bronze, and the outer ring is copper-nickel, thus giving them two colours; silver outer and gold inner appearance.
Hence, giving them two colours; silver outer and gold inner appearance. The inner circle (plug) is composed of two layers aluminium bronze, and the outer ring is copper-nickel.
The inner circle (plug) is composed of two layers aluminium bronze, and the outer ring is copper-nickel. Hence, giving them two colours; silver outer and gold inner appearance.
The inner circle (plug) is composed of two layers aluminium bronze, and the outer ring is copper-nickel. Hence, giving them two colours; silver outer and gold inner appearance.