Brooks' most-loved support shoe is smoother than ever. GuideRails holistic support system Brooks' unique technology aligns your body in its natural motion path while keeping excess movement in check. Smoother feel. Updated midsole is now 100% DNA LOFT cushioning for an even softer, smoother ride. Better transitions The new softer midsole and Segmented Crash Pad team up for easier flow from landing to toe-off. DNA LOFT now makes up the entire midsole. Simplified midsole construction creates more seamless transitions.More strategic use of 3D Fit Print technology provides structure that moves with the foot. Additional Benefits 3D Fit Print in saddle offers a supportive, secure fit.