By routinely replacing your shaver head, your shaver will stay at peak performance for years. Over 18 months your Braun electric shaver will cut over 6,000,000 hairs, gradually reducing cutting performance. To maintain your best shave, we recommend replacing the shaver head every 18 months. Li-Ion Battery for up to 3 weeks of shaving (50 min). 5 min quick charge for one full shave. AutoSense technology reads and adapts power to beard density. Shaving even dense beards. Flex Electric shaver for men with 360° adaptation for a smooth shave, even in tricky areas.