To replace the outer foil: Squeeze the old system outer foil release buttons and lift the outer foil upward to remove it. To insert the new system out foil, press down until it snaps into place. It is recommended that you replace the outer foil at least every year to maintain your shaver's cutting performance.
Foil and Cutter Cartridge Replacement Parts for Braun®'s Series 3
& 7000/4000 Series Models This replacement foil and cutter combo pack will fit the following Braun shavers: Model No. 4005, ...