Newton Gravity IV Running Shoes - AW15 Engineered mesh upper - Provides lightweight breathability and structure in key areas. Synthetic Overlays - Are anatomically placed to provide a secure fit. Flex Zone in the forefoot - Is a 4-way stretch material that offers a more individualized fit and greater toe splay. Slip-Proof Laces - Stay in place with heel-securing double eyelets. ETC Sockliner - Is anti-bacterial for underfoot comfort and a healthy foot environment.