Mouthpiece material: 100% High Quality Liquid Silicone Tube Material: 100% High Quality Liquid Silicone. Differentiated-section tube designed to ensure excellent breathing and allow the quick and effective expulsion of water. The choice of 100% silicone is essentially due to two aspects: it is the only material that does not change its characteristics and behaviour with the temperature and it is the only material that has memory to return to its original shape even after being deformed for long periods.