Rubber sole Shaft measures approximately Ankle Strap from arch A Zoom Air unit in the forefoot offers responsive cushioning. Every step helps create energy return to help drive you forward. It combines with a foam midsole for a firm, smooth and stable feeling as your foot hits the ground. Data from hundreds of runners helped inform the crash pad placement at the heel. It helps provide extra cushioning for heel-to-toe transitions, supporting runners that tend to overpronate. That info was also used to put cooling exactly where you need it on the upper. The durable rubber sole is built for mileage. Grooves in the forefoot to create flexibility, and vertical grooves down the side help create stability. Laces cinch down for a secure feel. Mesh is engineered for durability. Water Resistance Level: not_water_resistant The Nike Air Zoom Structure 24 is built for life in motion. It features soft cushioning and a unique textured design that improves both fit and comfort when you travel many miles. The newly designed, ventilated upper is based on data from runners and uses innovative mesh in key areas that improves cooling where you need it most.