Scubapro Synergy 2 Single lens Scuba Diving Mask Synergy2 Trufit Technology: The newest generation of Trufit technology features two separate silicone skirts. The main inner skirt is thin and soft to provide the best possible fit, seal and comfort against the skin. The outer skirt is thicker to provide support and rigidity near the mask frame. The silicone contouring the face is thinner, giving a softer feeling, for a truly unique fit and seal.