Another important inventor was Prof. Alexandre Horowitz, from Philips Laboratories in the Netherlands, who invented the concept of the revolving (rotary) electric razor. It has a shaving head consisting of cutters that cut off the hair entering the head of the razor at skin level.[6][7] Roland Ullmann from Braun in Germany was another inventor who was decisive for development of the modern electric razor.[8] He was the first to fuse rubber and metal elements on shavers[9] and developed more than 100 electrical razors for Braun.[10] In the course of his career Ullmann filed well over 100 patents for innovations in the context of dry shavers.[11] The major manufacturers introduce new improvements to the hair-cutting mechanism of their products every few years. Each manufacturer sells several different generations of cutting mechanism at the same time, and for each generation, several models with different features and accessories to reach various price points.