Brooks Glycerin Stealth Fit 21 Men's Running Shoes. Featuring the same ultra-soft cushioning as the Glycerin 21 and an adaptable fit for runners with a neutral stride, the Glycerin StealthFit 21 is flexible and streamlined. You'll feel your foot well supported. It now features more nitrogen-infused DNA LOFT v3 cushioning (2 mm) than ever before, the innovative universal full-body support system and sleek styling. It's a running shoe ready to take on any challenge. Features: Support: neutral. Surface: track, road. Innovative GuideRails technology allows your body to maintain its natural path of movement while limiting excessive movement. Soft flat-knit upper offers a blend of stretch and compression that follows your foot's movements. Sustainability: 64.4% recycled material in the upper; 1.38 plastic bottles diverted from landfill. Offset: 10 mm. Weight: 263.7 g (9.3 oz).