MSR D3O Hip Pad D3O Hip pads are compatible with all MSR Pants. D3O intelligent shock absorption is a patented shock absorbing material engineered with intelligent molecules. D3O is a rate-sensitive material. Meaning when moved slowly the molecules flow freely, making it soft and flexible. At high speeds (Like an impact) the molecules lock together making the material an excellent shock absorber. The whole process is repeatable occurs instantly and returns to its original state as soon as the impact is over.