30oz splash proof lids for most tumblers.

At lot of the knock off Yetis and even some of the yetis come with just an open lid so they are easy to spill. These lids slide shut so they are easy to take everywhere and fit almost all of the 30 tumblers well.  I have several sets and they seem to hold up well.  I even put mine on the top rack of the dishwasher to make sure they get clean.  However, the sliding part does clip off easily so you can wash them by hand too.  This is a great price for two of them.  I really like mine a lot.