very pliable material (kind of like Play-Doh) that becomes hard and tough upon impact. That means the pads are soft and flexible under normal conditions, but it's like a hard shell if you thump it into something. Sitting behind the D3O cup is a second foam shell to further diffuse the force of the impact. Out on the Trail Where these pads separate themselves from any other pad out there is on fit. The original Grenade Pro pads had a strap at the top and the bottom, like most other pads. Studying them, Scott realised that it meant the lower strap tightened halfway down the calf and could slip down relatively easily. On the Pro II, the strap has been moved up, just an inch or so, so that it sits at the top of the calf and uses the natural shape of your leg to keep it in place. Because they hold so well at the bottom, the advice from Scott is to barely tighten the top strap, allowing the blood to flow down your leg freely. All this adds up to a pad that stays in place incredibly well, without restricting your movement or circulation. In short, that makes the new pads very good to pedal in, which is surprising, considering the bulk of the pad. To reduce the bulk slightly, there is also the option of removing the foam pad from the knee - it pops out through a slit at the back - although we have