The dental kits available on the market include everything from special toothpaste to toothbrushes. As of July 11, 2019, he has released his own branded toothbrushes and toothpaste. Personal hygiene items such as soap and toothbrushes are also distributed. Nylon filaments are primarily used in brushes especially toothbrushes and string trimmers. Electric toothbrushes are a popular aid to oral hygiene. In 2000, Philips bought Optiva Corporation, the maker of Sonicare electric toothbrushes. Pig bristles were used for cheaper toothbrushes and badger hair for the more expensive ones. Examples of this would be using soft toothbrushes or nylon coated interproximal brushes. Inductive battery chargers are commonly used in electric toothbrushes and other devices used in bathrooms. The first application was for bristles for toothbrushes. Inductive charging is also used in vehicles, power tools, electric toothbrushes and medical devices. Many toothbrushes have wooden handles, often bamboo. Most sonic toothbrushes come with different cleaning modes and intensity levels. In the case of ultrasonic toothbrushes, ultrasonic motions are produced by a piezoelectric crystal. Some ultrasonic toothbrushes, such as the Emmi-Dent, provide only ultrasonic motion.