Very comfortable radiofrequency shielding for the head and thyroid region. Medical grade, silver coated stretchy fabric provides very good microwave shielding. Washable and very soft. Can be worn many ways: covering nose/mouth or not. Covering neck or not. Size of eye opening can be adjusted to your preference. Shielding performance decreases over time. Lightweight, stretchy, anti-bacterial fabric is the key. One size fits all.