In two years, the shaving heads cut a total of 9 million beard hairs. Replace the shaving heads to regain 100% performance. Compatible with the 3000 and 1000 series shaversCompatibilitySH30 (3er Pack) replacement shaving heads are compatible with 3000 (S3xxx), 1000 (S1xxx), and Star Wars SW3700 shaver.Reminder FunctionThe latest Philips shavers have a built-in reminder function in the form of a shaving unit symbol. This symbol lights up and indicates when you need to replace the shaving heads.Easy replacement1. Open the shaver with the release button2. Remove the bracket by turning the latch counterclockwise3. Remove the old shaving heads and carefully insert the new ones; make sure that the shaving heads are precisely aligned4. Replace the bracket and secure it by turning the latch clockwise5. When you close the shaving head properly, you hear it click into place.This will make your shaver almost like new againThe latest Philips shavers have a built-in reminder function that shows you