Make any glass cup a Sippy cup. The siliskin top is a silicone Sippy top that stretches over most standard size glass cups, turning the glass cup into a Sippy cup for kids. The siliskin Sippy top grips the top of a glass while air suction keeps it perfectly in place, preventing spills and leaks. Where form meets function, the innovative design makes the siliskin Sippy top a breeze to use, and it's not plastic. The unique Sippy top is also designed without unnecessary valves or cumbersome pieces. The Sippy top has no hidden crevices that are hard to reach where gunk and bacteria hide. The design allows for easy cleaning and care.