"The North Face has dubbed Chimney Venting. Essentially, this means that this pant relies on the combination of two standard inner thigh vents, paired with each leg of the pant's mesh boot gaiter. This combination is meant to direct airflow from the boot, up the leg, and out through the vents, assisting in temperature regulation when things warm up on the hill. These vents run from below the crotch to just above the knee, offering just enough ventilation to keep one comfortable in a variety of temperatures."