I have been searching for an adult sippy cup for almost 2 years - I have bought approximately 10 different types of cups hoping that one of them would work. The Veterans Administration sent me the Ark cup when I mentioned that I had not been able to find a spill proof cup for my spouse. It worked so well that I ordered 3 additional ones. This is a product which should be sold in pharmacies and stores around the country as an adult sippy cup. I probably should order a packet of the one way straws which would be even more protection against spillage.