Copper cathode.
Copper cathode.
Copper cathode.
Copper cathode.
Copper cathode.
Copper anodes and cathodes.
Copper cathode.
Copper cathode.
Copper cathodes.
Copper cathodes .
Copper cathodes.
Copper cathodes.
Copper cathode.
Copper cathode.
Copper cathode.
Copper cathode.
Copper cathodes.
Copper cathodes.
Copper cathodes.
Copper cathode.