Fewer refills equal more hydration—all thanks to the Owala 40oz Tumbler. But this is no ordinary insulated cup. Not only does it hold a whole lot of water, but it also has an awesome 2-in-1 lid. Want to sip? Use the sturdy, reusable straw. If swigging is more your thing, just remove the straw and sip through the spout. Another handy feature?