The average Braun shaver cuts 6 million hairs every 18 months. This means the head will gradually wear out and your shave can become less close and comfortable. That's why Braun recommends changing your shaver's foil & cutter block every 18 months to get your shaver back to its best. Take care of your shaver, and it will take care of you. Box includes: 1 X Series 9 Pro Shaver Head Replacement Features • Peak performance: to maintain your best shave, we recommend replacing the Series 9 Pro head every 18 months • The Series 9 Pro head capture's more hair in the first strokes, for an exceptionally gentle shave • Aiming for zero evening beard: the Pro Head with the unique Pro-Blade shaves hair below 0.05 mm delivering a close and gentle shave that lasts • Simple replacement: easily attach your new shaver head-just by clicking it on • Quality craftsmanship: 100% made in Germany and compatible with Braun Series 9 Pro and Series 9 shavers