?Customer First?: If you can't install it, you can refer to the instructions on the back of the package or contact us in time, we will solve it for you within 24 hours. ?How to use?: the replacement package includes a hypo-allergenic gold foil and a gold cutter bar assembly,Designed to get the closest shave possible without being painful or irritating. ?Fit model?: This Single Replacement Foil and Cutter compatible with any FXFS1/FXFS2 single foil shaver.When the foil and cutter on FXFS1/FXFS2 shaver are dull, you can change it. ?HIGHER QUALITY? :Replacement Shaving Head & Cutter Blades with Hypo-Allergenic Silver Foil Head with Bump Prevent Technology.