1. 【Compatible Product】Replacement shaver blade for Series 7, black, is a compatible product for F/C73S. This is not an authentic or genuine product. 2. 【Material】ABS + Stainless Steel. The titanium-coated replacement blade provides a better shaving experience. 3. 【Compatible Models】Series 7: 70-B1000s 70-B1200s 70-N1000s 70-N1200s 70-N4300cs 70-S1000s 70-S1200s 70-S4200cs 70-S7200cc 70-S7865cc. 4. 【Replacement Period】We recommend replacing the blades every 18 months to maintain the shaver's shaving performance. 5. 【Other】This is a cassette type with the foil and cutter integrated. It can be used with all shavers compatible with F/C73S. For ease of maintenance, the outer blade can be removed by pressing the sides of the handle.