In 2008, Brooks' flagship shoe introduced BioMoGo to the world. In 2009, the Trance 9 unveils the new and improved Progressive Diagonal Rollbar (PDRB®), delivering unsurpassed cushioning and effortless, but supportive, heel to toe transition. Did we mention plush? You'll feel so much premium plushness in these puppies, you may never want to take them off!