Super-soft cushioning with industry-leading support for supreme comfort. The Glycerin GTS 21 combines cushion and support thanks to GuideRails® technology, which helps align the body in its natural motion path for distraction- free comfort on the run.Now with more super-soft, nitrogen-infused DNA LOFT v3 cushioning that is optimized to be lightweight, responsive, and durable for plush comfort New, engineered warp knit upper is breathable and allows for a flexible, accommodating fit while staying soft against your foot Innovative technology supports your body in its natural motion path while keeping excess motion in check New RoadTack rubber includes recycled silica and is lightweight and durable Additional 2mm of DNA LOFT v3 midsole for a plush ride Made with recycled materials equivalent to 5 plastic water bottles Men's Brooks Glycerin Gts 21