The Gel-Kayano 12.1 features a design inspired by European gothic armour and its structural, metallic properties. Open mesh underlays improve airflow, while the midsole incorporates the tooling system from the Gel-Nimbus 17. The construction includes dual Gel technology inserts and a Fluidride cushioning structure. breathable mesh underlays Gel-Nimbus 17 tooling system Fluidride technology rearfoot and forefoot Gel technology dope dyed recycled sockliner mesh