very well. there is a rubber gasket on the ring, and that ring snaps tight onto your bucket, once you put it on it ain't coming off ever. then you have the lid that now threads into the top of your bucket and it has a rubber gasket as well. a 5 gallon bucket can hold alot of gear and what's great about is you can set your life jacket on it and it doubles as a camp chair.How well does that seal?