Mizuno Women's Wave Nirvana 7 Running Shoe 100% Mesh and synthetic Rubber sole New SmoothRide Engineering utilizes the maximum energy efficiency properties of both flexibile and stiff footwear Larger flex grooves maximize energy efficiency during the initial toe-off stages, whereas flex controllers maximize efficiency Dynamotion Fit - Design Technology that relieves the stress the foot naturally places on footwear, eliminating distortion for the perfect fit Mizuno Intercool - Full-length midsole ventilation system reduces heat and humidity build-up inside the shoe Gender Engineering - The lates engineering philosophy to maximize performance by tailoring footwear to the separate needs of men and women Flex lines for women and wider sole for men Mizuno Wave - The leading footwear technology that combines cushioning and stability, two distinctly different elements that are both inherently necessary in great running shoes