For women order 1.5 sizes down (ex. For a women's 8.5 order a unisex size 7.0)light speed.our lightest racing shoe the nike zoomx streakfly is all about the speed you need to take on the competition in a mile 5k or 10k race. Low profile with sleek details it feels like it disappears on your foot to help you better connect with the road on the way to your personal best.low and nimblea full-length zoomx midsole provides the ultimate lightweight responsiveness. The foam stack heights are lower than the vaporfly saving weight and giving you a more aggressive feel. It results in a shoe so light it disappears on your foot while still giving you the responsive protection of zoomx foam helping you reach your fastest pace throughout the turns and accelerations of any race.supportive and sleekan ultra-thin knit upper is light in weight while still providing the support you need for racing. Extra reinforcement in the forefoot keeps you secure. The updated sleek lacing system is laterally offset with a notched tongue to help relieve pressure on the top of the foot.grip where it countsrunner-informed data was used to create the outsole. It uses that information to place traction where you need it the most with a pattern that connects to the pavement based on how your foot hits the ground. The result is solid grip from foot contact to toe-off helping you stay ahead of the competition.partially integrated tongue delivers a secure fit.