J & M - C2809 - Reactivate U-Throat (Black)Our lightest, most breathable construction yet. In the softest perforated nubuck or full grain leather, plus a new extra breathable leather thats specially processed to optimize air flow, so its twice as breathable as traditional leather. High rebound ventilated EVA sole maximizes the flexible comfort. Temperature adjusting J&M Smart Degree Technology activates at both hot and cold temperatures, maintaining a higher degree of comfort, so your feet