Run like there's no finish line in the Brooks Glycerin 21. Engineered to help you find your strength with every mile, these runners promote smooth heel-to-toe transitions and support every stride to help you conquer your daily miles. The nitrogen-infused DNA LOFT v3 cushioning puts a spring under your step and absorbs every impact, while the new RoadTack rubber adds resilience to your long miles. Run to the beat of your own pace in the Brooks Glycerin 21. Brooks Glycerin 21 features: New engineered warp knit upper provides structure in crucial locations. Broad platform stabilizes the foot and promotes smooth heel-to-toe transitions. 2mm of DNA LOFT v3 underfoot offers even more plush cushioning. Stack height to 28:18 for a 10mm offset. Weight: 9.8 oz.