These face masks offer the airflow you need, a cool feel, and the best fit for running or training. The 3-Layer system features; Layer 1: Spacer fabric – it’s light with air pockets to create structure, so it can stay off your mouth and nose for better airflow. Layer 2: Open-cell foam - the breathable middle layer lets air through but makes it hard for moisture and sweat to pass. Layer 3: UA Iso-Chill technology - this fabric actually feels cool against your skin, stretches, and has antimicrobial treatment.