Manual operation. Waterproof, no battery required. Perfect for various hairstyles from thick to thin, short or long, and no matter wet or dry, even to groom hair of your pets. Taking shower with this soft shampoo brush makes your hair and scalp cleaner than before. A soft and high-quality hair brush provides you an enjoyable washing experience. Massaging your scalp in the shower to ease itchiness and promote blood circulation, promotes hair growth and reduce tension headache symptoms. Getting a relaxing massage at home and every time you wash your hair. Ergonomic design perfectly fits in your palm and is easy to hold. Only 1.8 Oz, lightweight and stores easily. Excellent scalp massager is suitable for who has long and manicured nails, you won't damage your manicure during washing hair anymore