The Siliskin Training Cup is an 8oz glass sippy cup encased in a heavy-duty and patented shock absorbing silicone sleeve (a Siliskin). The Siliskin gives added protection to the glass inside and extra grip for little hands. The silicone top stretches over and grips the top of the glass while air suction keeps the top in place for no spills or leaks. Dishwasher and microwave safe. Hypo-allergenic and BPA free.Silikids