This waterproof bag is perfect for protecting your things - like keys, wallets, phones, etc... from the water. Once the bag is rolled shut and secured, everything inside is safe from splashes, waves, and spray. Not completely waterproof under water, unless the bag drops overboard and you grab it right away. Great find! You can secure it to yourself or the boat by threading the handles through a belt loop or something that won't break before you snap it together. I'm sure I'll be buying more of these!