Concord Keystone has released the US$39.99 Keystone ECO MarineCase (http://macte.ch/W8pfL), a fully submersible case for the iPhone 4S/4 that purportedly keeps the Apple smartphone 100% dry and safe at depths of up to 20 ft/6m underwater.
The MarineCase is designed specifically for in-water use such as swimming, kayaking, white water rafting, boating, fishing, or for almost any water activity or sport. It also protects the iPhone 4S/4 against sand when you are at the beach.
The MarineCase is IP58 certified (dustproof and waterproof). It’s available in black or white and comes with a neck strap.