Gillette uses miniature cameras to get at the core interactions between its products and their users. While Gillette Co., Boston, is actively observing and videotaping men and women shaving and brushing teeth, it also uses microcameras to observe the interaction of brush and tooth, blade and whisker. In the development of the premium-priced Oral B Cross Action toothbrush, for instance, a miniature high-speed video camera was placed inside a model of a mouth that included one transparent tooth. Examining some 50 prototypes of bristle design, Gillette videotaped the action of the bristles through the clear tooth as the brush moved across the teeth. This showed that cleaning took place most effectively when the bristles changed direction as the brush moved across the teeth and that angling the bristles in a crisscross fashion increased this effect. That led to the design just now being marketed at premium prices. Microcameras also are applied in shaving research that has led to multiple iterations of Gillette shaving instruments. "Effectively we have video cameras on the end of microscopes that are focused on the facial hairs," says John Terry, vice president for corporate R&D. "As the razor goes across the hairs we can see how the blades cut them and how the skin deforms. This observation has fueled a lot of the developments of new razors from Track II through today's Mach III. When you see it in real life, there are a lot of other facial hairs around, so to clarify what is happening and make the message clear in our advertisements, we use the simplified depictions you see on TV. But that exactly mirrors what we see in real life."