What is Wonder Cup? Wonder Cup is a sippy cup that is designed to work with baby bottle nipples to control the flow of milk for babies that want to hold their own bottles. Many babies and toddlers want to hold their own bottles and cups, but aren’t ready for the free-flowing spouts of big kid sippy cups. Wonder Cup combines the easy-to-hold design of a sippy cup with the flow control and comfort of a baby bottle. Wonder Cup features comfortable handles, a secure lid, and a set of interchangeable nipples that offer flow control without leaks. Wonder Cup is an all-in-one solution that makes it easy to transition from bottles to cups without needing to buy multiple separate accessories.