the tumbler lid turns any 8oz, 16oz and 20oz insulated tumbler and 16oz and 20oz steel pint into a perfect to-go cup. the splash-resistant press fit lid has an easy to clean design with removable silicone gasket. tumbler lid is made from bpa-free polypropylene #5 and is dishwasher safe. note: tumbler lid is not leakproof.