Originally Posted by JAMMINKRAZY

Sure. See what happens in a normal shock is the air behind the bladder will heat up and expand throughout the course of a long race. This will change your rebound and in turn also change your ride height. That makes for different handling at the end of a race vs. the beginning. The vented cap allows the air behind the bladder to escape. The foam is then used to provide the support behind the bladder that the air pressure normally would however unlike the air, the foam won't change. By the foam providing consistant pressure behind the bladder your rebound and ride height stay the same from beginning to end of a race. That's what makes the handling consistant throughout the race.