The Professional features the most advanced mouthguard technology available in the world. Made from two distinct materials; the hard inner Shock Transfer Core tranfers impact from the fragile front teeth to the strong molar teeth. The soft outer layer moulds tightly to the teeth providing a comfortable fit, and allows the Stealth2 to be thin on the inside, next to the tongue. This means speech is not impaired at all. This mouthguard is mouldable and works with boil and bite system (instructions are in the packaging).