The spill-proof cup rim is made of silicone and is easy to clean. A gentle pressure from the lips can start the flow of drink and allow for self-regulation of drinking speed. This Wonder Cup is perfect for on-the-go use. It provides your little one with the ideal support to drink like the big kids, as the 360° rim allows drinking from any point around the cup. Hygiene is a priority for Nuby products, which is why Nuby has designed an easy-to-clean protective cap for the Wonder Cup. Of course, cleaning in the top rack of the dishwasher is also not a problem. The Easy Grip handles are specially designed for your child's small hands, making it easy to hold the cup.