That sounds like a product looking for a market to me. Foam is used for burning liquid fires because it floats on top and prevents oxygen from reaching the fuel. It is not very conductive and can be used on electrical fires with liquid fuel, but a complete blanket must be formed, thus one needs a lot. For "normal" electrical fires, such as appliances, a dry powder is probably just as good, and easier to clean up afterwards. I wonder where this would be used domestically, it would be unwise for a chip pan where a cloth is just fine? It might be useful in a car and could be useful in a hybrid, where the battery voltage is a (slight) risk, but seeing a circuit via the operator is somewhat difficult. At home, a decent size (not 2 litres) CO2 or dry powder is more than adequate, and very few actually get used. Two litres might put out the petrol lawnmower, but probably not if it was full of fuel. I presume this comes with a video where it is shown working?
Similar extinguishers have been on the market for a few years now, you can Google water mist extinguishers these too are all risk scenario extinguishers.
