Which of the following is NOT a characteristic of wet chemical extinguishers?

Wet chemical extinguishers are specifically designed for use on cooking fires, particularly those involving oils and fats, which are common in kitchen environments. They primarily work by providing a cooling effect and effectively smothering the fire, which helps to extinguish it. However, they are not suitable for flammable gas fires, as these types of fires require different extinguishing methods and agents.

The other options highlight characteristics that wet chemical extinguishers possess or are intended for, such as their effectiveness against electrical fires and their cooling and smothering properties. This distinction emphasizes the importance of understanding the specific applications of different types of extinguishers to ensure safety and effectiveness in firefighting situations.