The ioSafe external hard drive is almost completely disaster-proof. It can withstand temperatures up to 1550º F, can withstand being immersed in up to 10 feet of water for up to 36 hours and, on NAS and USD-RAID models - not the

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Solo - rebar-reinforced crush-zones enable the hard drive to survive the collapse of a two story building. Additionally, as a theft-protection measure, the ioSafe has holes bored in its shell so that it can easily be bolted to the floor.
In short, whether your house is flooded, burned to a cinder or flattened by a tornado, the data on the ioSafe will still be intact. The video on the company's website shows an ioSafe hard drive being burned and broiled, and it's data surviving (this is seriously impressive - be sure to check it out!).
Should the ioSafe not be in working order after a disaster, the company will attempt to recover the data - at their expense - and ship it back to you together with a new ioSafe. Should ioSafe not be able to recover the data, the company will pay up to $1000 to have a third-party data recovery service attempt to recover it. Note that ioSafe's data recovery service only applies for 12 months after purchase, but can be extended for up to 5 years.