From Manufacturer site- New to Newton? We fit snug for most. Add a 1/2 size for best fit. (US Sizing Displayed) specifications * Weight: 6.8 oz * Drop: 3.0mm * Support: Neutral * Certified Vegan * Sustainably Constructed upper * Women's specific design/fit * 3-D engineered air mesh * Plush, breathable seamless construction * Multi-positional lacing system * Upper constructed of 100% recycled materials sole technology * NEW Newtonium-T Midsole * XPS+ Pebax Plating system * High Performance Action Reaction Technology™ * Full-Foot Newtonium Cushioning * Hytrel® foam footbed More about Us Boulder, Colorado-based Newton Running is the leader in performance running shoes that promote gait efficiency for people at all levels of the sport, from first-time 5k runners to seasoned marathoners. Newton Running’s patented Action/Reaction™ technology provides dynamic shock absorption, energy return, ground feel, minimal heel-to-toe drop, and lightweight comfort. Newton Running form clinics, hosted in partnership with specialty running retailers worldwide, help runners learn their natural running motion.