The Electric razor consists of a set of oscillating or rotating blades, which are held behind a perforated metal foil that prevents them coming into contact with the skin. Bristles poke through holes in the foil and are sliced by the moving blades. In some designs the blades are a rotating cylinder, in others they are one or more rotating disks, and in others a set of oscillating blades. Each design has an optimum motion over the skin for the best shave and manufacturers provide guidance on this. Generally for circular blades it is a circular motion and for cylindrical or oscillating blades it is up and down. The first electric razor was built in 1928. Goodman's carries an assortment of women's electric shavers.