The first electric razors were developed in the late 1920s and the 1930s. Two companies that still produce a variety of razors today were the innovators of electric razors, Schick and Remington. Over the years, there have been many different styles of powered razors developed. The two most common styles are rotary and foil shavers, and both are built on similar principles.
Both types of razors have an element called a foil that traps hair. This allows the blades inside the electric razor to then cut the trapped pieces of hair. In rotary razors, there are three foils, and three sets of cutters or blades. On the surface of the razor, this looks like three spinning heads.
Most electric razors are similar across the board on warranty coverage, which is usually two years. However, others may last up to a few years or even for five depending on the razor.