The breathability of a fabric is measured in RET (Resistance to Evaporative Heat Transfer). The lower the fabric's resistance, the more water vapour generated by an active body escapes through the fabric, and the higher the fabric's breathability. The complex RET is the measurement performed on a finished product. The Steppe 100 cap has 6 eyelets for ventilation around the head.
Store in a dry well-ventilated place. Keep away from fire.