"All extinguishers in the UK used to be specific colours, Black for CO2, red for water, white/cream for Foam, blue for powder I think,, they each have different uses and some are dangerous, e.g. water on an electrical fire, hence the need for different properties and the colours to tell them apart. More recently the EU rules have meant all extinguishers must be RED so they can easily be seen in an emergency, but they still retain coloured labels to differentiate what is inside them. I think these black and white ones could be dangerous for use by anyone with a knowledge of this stuff, but I guess they are unlikely to find them anyway ;)"