The WDF4839AU The dual sided flexible trimmer ensures no hairs are missed, lifting and trimming flat laying hairs from both directions. The long lasting cordless operation means you have up to 30 mins of cordless run-time for added convenience, as well as being 100% waterproof for an easy and comfortable shave in the bath or shower. The Ultimate Shave & Trim also includes a bikini trimmer for all your precision bikini grooming and trimming needs.