Corkcicle Tumbler lids are designed to be spill-resistant so you don’t have to worry about any major spills. However, it’s not designed to be completely leak-proof. There is a tiny steam hold on the top of the slider piece, so be sure to keep your Tumbler upright when you’re on the go.
Our Canteens on the other hand are completely leak-proof! If you're looking for a product you can toss in your bag with no worries, Canteen is the choice for you.
If your Tumbler is leaking from where the edge of the cup and the lid meet, it may be an issue with your lid’s rubber gasket. Please ensure the flat side of the gasket is resting flat in the groove on the lid. Now, simultaneously twist the lid as if you were screwing it on, and push the lid down to create a great seal. If you push the lid straight down on to the tumbler, the gasket may "roll" out of place and cause the lid to pop back up. Here’s a handy video to give you a visual as well.