Looking to increase speed or distance? The updated Women's Brooks Glycerin Stealthfit GTS 21 is crafted to accommodate, with custom-fit contouring that feels one with your foot. Packed with updates such as the new RoadTack rubber, that includes recycled silica, for superior grip no matter the surface and an additional 2mm of DNA LOFT v3 midsole cushioning for extra bounce. Not only is the Glycerin Stealthfit 21 an ultra-comfortable, lightweight, durable shoe but it is working hard to protect the planet on whatever route or terrain you decide to take it on!