At rest, the molecules inside d3o move freely, making it soft and
flexible, while at the point of impact or shock, the molecules lock
together to spread and absorb the force, safeguarding your valuable
product in a protective layer.
Tech 21 claims d30 "[o]ffers 120% to 150% more protection than other cases." One would hope so, with suggest retail prices in the ¬£19.95-¬£24.95 range — and as someone has already pointed out, that protection doesn't extend to the screen, which (in France, at least!) is most likely to shatter unexpectedly.
Here's a video of this "iFlubber" in action: