For the ERKODENT mouthguard PLAYSAFE Heavy-Pro and Light-pro. Chemical characteristics: Physiologically harmless, BGA (Federal Health Office) listed polystyrene (styrene butadien co-polymer). Insoluble in water. Can be recycled. Odour-free. Inactive - harmless to ground water. Completely combustible, low in pollutants and high in energy (useful components for waste combustion).