Women's Running ShoeThe new Glycerin 19, packed with DNA LOFT cushioning throughout the full-length of the midsole, delivers a softer experience from heel to toe than ever before. And, it also comes with the option of GuideRails technology for whole-body support. These sneakers provide the support you need to run comfortably in the Glycerin GTS 19 with GuideRails technology. Located in the midsole, and engineered with your knees in mind, GuideRails technology helps you move comfortably by keeping excess movement in check. Details -- Synthetic upper and sole.