Signature CloudTec Cloud elements are Swiss-engineered to deliver a soft landing followed by an explosive take-off. The result? A light, responsive sensation that goes as long as you do. All day. Every day. Tighter athletic upper An athletic upper arrives in a tighter fit for added security and an extra snug step-in feel. A layered mesh fabric on the tongue offers an optimum air circulation. The unique elastic function works in a net structure to provide plenty of stretch and breathability. Speed-lacing system Laces packed with stretch-power flex to allow your foot slip in quickly, then rebound back in place to hold you securely. Fast to pull-on so you don't waste any time.