SteelPrecision blades with automatic sharpening system: The 45 SteelPrecision blades cut up to 90,000 times per minute for a close shave. The automatic sharpening system ensures a consistently sharp cutting performance. Beard density sensor: The sensor detects beard density 250 times per second and automatically adjusts the power to match the thickness of the beard. It effortlessly shaves even thick areas. 360-D Flex Head: The flexible head rotates 360° and follows the contours of your face. It closely adheres to the uneven surfaces of your face, minimizing missed spots.