The DefenderShield® EMF Radiation Protection Baseball Cap offers comfortable and modern Electromagnetic Field (EMF) radiation protection for your head. It is made from lightweight nylon blended with spandex, and features advanced wireless EMF shielding material woven inside the dome of the Cap. The DefenderShield EMF Cap also blocks UV light, to protect your head from sun damage. It can be worn day or night, in both cold and temperate climates.