The fillings are in expanded polyurethane a polymer that is both solid and elastic and has an open cell structure: produced in blocks of varying density that can be cut or sawn depending on the characteristics of the model.
They don’t contain substances that are harmful to health or damage the ozone layer. Polyurethane that is used nowadays, is breathable, antibacterial and guarantees to maintain a high level of elasticity over time. The materials can on request contain a fire retardant that has been tested and certified as conforming to regulation.