Philips SH91 Replacement HeadsWithin two years your shaver heads cut 9 million hairs on your face. Replace the shaver heads and get back to 100% performance. Skin level closeness NanoTech DualPrecision blades shave close precisely at skin level (up to 0. 08 mm below the skin), performing up to 165,000 cutting actions per minute. The 72 high performance blades are self sharpening and made in Europe. For shavers series 8000, 9000 and 9000 Prestige Check the back of your shaver's