Just a bit more info on d3o:

d3o (dee-three-oh) is a specially engineered material made with intelligent molecules. They flow with you as you move but on shock lock together to absorb the impact energy.

d3o components all utilises the unique Flow texture specifically designed to provide optimal freedom of movement and exceptional protection due to the macro-densifying mechanism which maximizes contact and therefore minimizes pressure transmitted during impact. This protector is also breathable for ultimate comfort.

http://d3olab.com