The GoSili Sippy Cup is 100% silicone with an embedded stainless steel ring keeping it from collapsing when squeezed. The sippy cup comes with a universal silicone​ sippy top that fits over any size cup. The spout is also free of intricate valves allowing for easy cleaning and easier use. Perfect for on-the-go, tabletop, indoor and outdoor use. Excellent for preventing big spills!