Wikipedia
Electric knife
An electric knife or electric carving knife is an electrical kitchen device used for slicing foods. An electric knife requires less physical effort than an ordinary knife and produces neater slices. The device consists of two serrated blades that are clipped together. When the appliance is switched on, the blades continuously move lengthways to provide the sawing action. In the UK, electric knives were popular in the 1970s and not as popular in today's kitchens.