Similar to Avent's magic cup. I received this as a gift from family - you can change out the top portion - you can start with a nipple, move to a sippy cup, then to a straw and finally to a mug (similar to travel mug). The best part of this one is that steps 2, 3 and 4 have lids. So, you can snap the lid closed and lock it to keep it from spilling.